Let's deal with that second one first. The only artifacts that "turn off" when tapped are those where their current oracle wording says they do. Winter Orb and Howling Mine are two examples of such cards, but Trinisphere, Static Orb, Watchdog, Storage Matrix, and I think one or two more also work that way.
Tangle Wire does not, nor would any other random artifact.
As for the Op/Op/Hum question, this changed a little with 8th edition rules.
418. Continuous Effects
418.1. A continuous effect modifies characteristics of objects or modifies the rules of the game for a fixed or indefinite period. A continuous effect may be generated by the resolution of a spell or ability or by a static ability of an object.
418.2. Continuous effects that modify characteristics of permanents do so simultaneously with the permanent coming into play. They don’t wait until the permanent is in play and then change it. Because such effects apply as the permanent comes into play, apply them before determining whether the permanent will cause an ability to trigger when it comes into play.
418.3. Continuous Effects from Spells or Abilities
418.3a A continuous effect generated by the resolution of a spell or ability lasts as long as stated by the spell or ability creating it (such as “until end of turn”). If no duration is stated, it lasts until the end of the game.
418.3b Continuous effects from spells, activated abilities, and triggered abilities that modify the characteristics or change the controller of one or more objects don’t affect objects that weren’t affected when the continuous effect began. Note that these work differently than continuous effects from static abilities. Continuous effects that don’t modify characteristics or change the controller of objects modify the rules of the game, so they can affect objects that weren’t affected when the continuous effect began.
Example: An effect that reads “All white creatures get +1/+1 until end of turn” gives the bonus to all permanents that are white creatures when the spell or ability resolves—even if they change color later—and doesn’t affect those that come into play or turn white afterward.
Example: An effect that reads “Prevent all damage creatures would deal this turn” doesn’t modify any object’s characteristics, so it’s modifying the rules of the game. That means the effect will apply even to damage from creatures that weren’t in play when the continuous effect began. It also affects damage from permanents that become creatures later in the turn.
418.3c If a resolving spell or ability that creates a continuous effect contains a variable, the value of that variable is determined only once, on resolution. See rule 413.2f.
418.3d Some effects from activated or triggered abilities have durations worded “as long as . . . .” If the “as long as” duration ends between the end of playing the activated ability or putting the triggered ability onto the stack and the moment when the effect would first be applied, the effect does nothing. It doesn’t start and immediately stop again, and it doesn’t last forever.
Example: Endoskeleton is an artifact with an activated ability that reads “{o2}, {oT}: Target creature gets +0/+3 as long as Endoskeleton remains tapped.” If you play this ability and then Endoskeleton becomes untapped before the ability resolves, it does nothing, because its duration—remaining tapped—was over before the effect began.
418.4. Continuous Effects from Static Abilities
418.4a A continuous effect generated by a static ability isn’t “locked in”; it applies at any given moment to whatever its text indicates.
418.4b The effect applies at all times that the permanent generating it is in play or the object generating it is in the appropriate zone.
Example: A permanent with the static ability “All white creatures get +1/+1” generates an effect that continuously gives +1/+1 to each white creature in play. If a creature becomes white, it gets this bonus; a creature that stops being white loses it. A creature spell that would normally create a 1/1 white creature instead creates a 2/2 white creature. The creature doesn’t come into play as 1/1 and then change to 2/2.
418.5. Interaction of Continuous Effects
418.5a The values of an object's characteristics are determined by starting with the actual object, then applying continuous effects in a series of layers in the following order: (1) copy effects (see rule 503, "Copying Objects"), (2) control-changing effects, (3) text- changing effects, (4) type-, subtype-, and supertype-changing effects, (5) all other continuous effects, except those that change power or toughness, and (6) power- or toughness-changing effects. Inside each layer, apply effects from characteristic-setting abilities first, then effects from all other abilities. For power- or toughness-changing effects, apply changes from counters after changes from characteristic-setting abilities. See also the rules for timestamp order and dependency (rules 418.5b-418.5g).
* If a single ability creates multiple different effects and those effects could be applied in more than one layer (such as an ability that creates effects that set permanent type, color, and power/toughness), apply each of the effects in the appropriate layer.
* The revised rule means that nearly all continuous effects work as players expect them to.
* Some effects, such as Humility's effect, have been clarified by this change. Humility doesn't affect any type-, supertype- or subtype- changing effects at all, so the scenario of Opalescence + Opalescence + Humility, which had been really confusing, is now simple to handle. Opalescence creates a type-changing effect. Humility creates an "other" effect and a power/toughness-changing effect. Opalescence's effect is always applied before Humility's effects. As a result, all enchantments are 1/1 creatures with no abilities if Humility and one or more Opalescences are in play.
418.5b Sometimes the results of one effect determine whether another effect applies or what it does. For example, one effect might read, “All white creatures get +1/+1” and another, “Enchanted creature is white.”
418.5c An effect is said to “depend on” another if (a) it is applied at the same time as the other effect (see rule 418.5a) and (b) applying the other would change the text or the existence of the first effect, what it applies to, or what it does to any of the things it applies to. Otherwise, the effect is considered to be independent of the other effect.
418.5d Whenever one effect depends on another, the independent one is applied first. If several dependent effects form a loop, or if none depends on another, they’re applied in “timestamp order.”
418.5e An object’s timestamp is the time it entered the zone it’s currently in, with three exceptions: (1) If two or more objects enter a zone (or zones) simultaneously, the active player determines their timestamp order at the time they enter that zone. (2) Whenever a local enchantment becomes attached to a permanent, the enchantment receives a new timestamp. (3) Permanents that phase in keep the same timestamps they had when they phased out.
418.5f Continuous effects generated by static abilities have the same timestamp as the object that generated them.
418.5g Continuous effects generated by the resolution of a spell or ability receive a timestamp at the time they’re created.
418.5h One continuous effect can override another.
Example: Two enchantments are played on the same creature: “Enchanted creature gains flying” and “Enchanted creature loses flying.” Neither of these depends on the other, since nothing changes what they affect or what they’re doing to it. Applying them in timestamp order means the one that was generated last “wins.” It’s irrelevant whether an effect is temporary (such as “Target creature loses flying until end of turn”) or global (such as “All creatures lose flying”).
418.5i Some effects can switch a creature’s power and toughness. When they’re applied, they take the value of power and apply it to the object’s toughness, and take the object’s toughness and apply it to the object’s power. Any effects that are applied after the switching effect apply normally.
Example: A 1/3 creature is given +0/+1 by an effect. Then another effect switches the creature’s power and toughness. Its new power and toughness is 4/1. After the “switch” effect resolves, another effect gives it +5/+0. Its power and toughness is 9/1.
Example: A 1/3 creature is given +0/+1 by an effect. Then another effect switches the creature’s power and toughness. Its new power and toughness is 4/1. If the +0/+1 effect ends before the switch effect ends, it becomes a 3/1.
To repeat:
418.5d Whenever one effect depends on another, the independent one is applied first. If several dependent effects form a loop, or if none depends on another, they’re applied in “timestamp order.”So, you apply both Opalescences, making all the enchantments (even Humility) into creatures. Then, Humility makes them all 1/1s with no abilities (along with the rest of the creatures).
