I thought of this, too. When you go strictly by the rules, you are right, I think. Temporary aspects need fate points, too after the first tagging.
So, either you push rules aside when it makes no senso to you - you could even decide this differently from scene to scene - or you try to be creative. In your scenario, the bad guys can sprint around the furniture. Or, after the first round, they simply have adapted and shoot through it (I don't think a normal piece of furniture can withstand bullets) and a dodge roll is interpreted as leaving the cover.

Brewing a poison would be craftin IMO, but knowing which ingredients to use for certain effects should be knowledge.
basically the same for demolitions. Aüpplying demolitions to a building should be crafting, but knowing which explosive is the best for a special purpose and doing the math is knowledge, potentially with a stunt...

Well, actually the Old Man sacrificed his eye to see more than mortal eyes could, so how about something simular? I would assume that his magic is that, so that it replaces his lost hand. Not in a literal way, however. He could use spells to manipulate things or use a magic hand (made of ice) on a distance. However, I would avoid "repairing" the sacrifice with the magic given by that sacrifice, so just adding an icy hand on the stumo is like cheating in my opinion...

You're right. I didn't see the aspects at the bottom of the sheet...

The Catch, as described in the book, requires players to take one, that doesn't mean that NPCs need to have a Catch.

Are you sure about this one? I would think that such game mechanisms should alwys apply to everyone. This certainly includes exceptions, but these should be just that.
That said, in the case of Zombies I see no problem leaving them as they are. The weaknesses described - lack of free will (and combat tactics...), the inability to recover from consequences - should be enough to compensate for the catch.

or, maybe an aspect like "I have seen things I didn't want to and neither shouldn't" as a reference to the program where the wizard occasionally found more in the minds of his peers than a single word...

Hi,
I tried to make a spell who can enhance or change one or more senses of a wizard. So, obviously, magic could be used to give the wizard a +2 to alertness or investigation rolls because he is much mor aware of the things around him. But what if he want's to hear in the ultrasonic spectrum or see in the dark? First, I'm not sure how to handle such spells and second. I would like to have an intime explanation what happens to the wizards senses (or perceptive organs) to be able to sense in such a way.

The scene of an active volcano would have more aspects related to fire. Maby BURSTING FLAMES and HOT LIKE HELL in addition to your aspect mentioned. So a wizard could tap several aspects at once - provided he has enough fate points.