Short answer: The Man Lands will be 1/1s until end of turn.
Longer answer: From CrystalKeep's errata on Humility
When figuring out your creatures' abilities and power/toughness, apply all card effects in the order they entered play. Built-in abilities of a creature and any counters on the creature are applied first. Then, you apply all external effects in the order they entered play. The result of this is that any effects on the creatures' abilities or power/toughness in play before Humility enters play are completely overridden. But that any played after Humility enters play stay.
So, apply the man land's internal ability of the land being a creature at some power/toughness, then apply Humility's effect of making the creature a 1/1 with no abilities. The result is a vanilla 1/1. And yes, the effect of being a creature until end of turn as created by the man land is not affected by Humility, so the man land will revert back at end of turn.