If my opponent has an Oath in play, and he gives me a token via orchard, but I lava dart it, and none of us have any creatures in play after the dart resolves, can he give me another token during his upkeep and then stack the Oath so that he gets Akroma?

Also, if I have reprisals, and I kill my opponent's Akroma/Razia, can he Oath, reveal all his cards in his library (one of which is Gaea's Blessing) shuffle them into his library, and continue Oathing to get his Akroma/Razia?

Thank you.

I'm going to apologize up front about this post, I'm sorry, I'm new to the format, and I want to understand some of the complications with Stax - I don't have a big metagame where I'm from, but a bunch of my friends really like playing the decks, but we're not sure if we're doing everything right.  Hopefully you all can help me with it?

Smokestack's current rules text (oracle) is:

At the beginning of your upkeep, you may put a soot counter on Smokestack.
At the beginning of each player’s upkeep, that player sacrifices a permanent for each soot counter on Smokestack.

Can I put the "At the beginning of your upkeep, you may put a soot counter on Smokestack" on the stack, then immediately after, while the first ability has not resolved, put the "At the beginning of each player’s upkeep, that player sacrifices a permanent for each soot counter on Smokestack" so that I don't have to sacrifice anything during this upkeep, but I still get the counter?  That's how we've been playing, and we've been wondering if it's accurate.

Also, if the Smokestack has four soot counters on it, and I sacrifice the Smokestack to itself, I STILL have to sacrifice three more permanants, correct?  (We've also been playing like this.)

Goblin Welder:  A REALLY basic question, I'm sorry about this:

During my upkeep step, at the beginning of my upkeep, can I use Goblin Welder to weld out a Smokestack with three soot counters on it for a sootless Smokestack in my graveyard, so I don't have to sacrifice a bunch of permanents?

Also, I could just weld out the Smokestack during my untap step, after untapping Goblin Welder, right?

Uba Mask:

Uba Mask's oracle is this:

If a player would draw a card, that player removes that card from the game face up instead.
Each player may play cards he or she removed from the game with Uba Mask this turn.

I think I know how the Uba Mask/Goblin Welder trick works after reading a good bit on this website. 

How it works is after they reveal the card that they drew, you can use Goblin Welder to weld out the Uba Mask for another artifact, and then they can't ever play that card, but I have a question:

If they reveal a darkblast or lava dart (which are instants), can they target my welder before I weld out the Uba Mask?  We've been playing that the player drawing the instant can use the instant, but if they can't, that'd be nice to know.

Also, if I weld out Uba Mask 1 FOR Uba Mask 2 in my graveyard, they don't get the card, right?

Also, I can't use Mishra's Workshop mana for artifact's activated abilites, right?  Someone told me that you could, and I told him that the card and oracle just says playing artifacts.

This is a silly question, but can I imprint Duplicant onto itself?  The oracle says:

Imprint — When Duplicant comes into play, you may remove target nontoken creature from the game. (The removed card is imprinted on this artifact.)
As long as a creature card is imprinted on Duplicant, Duplicant has the power, toughness, and creature types of the last creature card imprinted on it. It's still a Shapeshifter.

If I _can_ remove Duplicant from the game by using it's own ability on itself, and I drew it this turn with an Uba Mask in play, could I play it again and do the same thing?

For instance, let's say I have about 100 mana because I have a crucible of worlds, fastbond, wasteland, and tolarian academy out in addition to my 20 artifacts.

I have an Uba Mask and a Pandemonium [Whenever a creature comes into play, that creature’s controller may have it deal damage equal to its power to target creature or player of his or her choice.] in play.  I untap, do nothing during my upkeep, and RevealFromGame a Duplicant because of the Uba Mask.  I then play Duplicant, RFG it with it's own ability, do that 16 times and win.

Is this sound?

Also, isn't this the sweetest kill ever?  Heh.

Also, what happens if I have a pandemonium in play and I Duplicant a Darksteel Colossus?  Do I do 2 damage to a target or 11?

Do I get to pick in which order the abilities stack, and so can I change it to 11?  For instance:  I can stack the Pandemonium's come into play ability first, then the duplicant's imprint ability, so that the duplicant's imprint ability happens first, and the Pandemonium's ability THEN looks at Duplicant's power?

Pandemonium's ruling things:

Oct 4, 2004 - The triggered ability does not check the creature's power until the ability resolves. If the creature is not in play when the ability resolves, it does damage equal to the power of the creature right before it left play. This means that if a creature comes into play which can destroy itself as a "comes into play" ability, the order of resolution of the triggered abilities does not matter.

Does this mean it'll do 11 damage if I stack it like I said above?

Thanks for answering all these questions.  I bet I have more, but I just can't remember all of them right now.  Thanks!