Hi there Lord Raziere. I believe Happy has answered the first, third and fourth question adequately enough. On the second question tough I think maybe I can help.

First, limiting it is a good idea, I mean we all can't have adamantium exo-suits because that would just be silly and overpowered. Very powerful things are rare for a reason, so everyone doesn't have the same super power.

Second, antimatter. I'm talking about matter that when it comes into contact with normal matter they both stop existing.

Third, black holes and extra-dimensional transportation. Black holes eat everything no matter how indestructible it is. Black holes will just make it part of itself. Now teleporting or creating portals could also work here. With teleporting if it's stopped part of the way through it just becomes scattered atoms. Cutting off a portal would cause whatever it is to now be severed in half on each end.

I guess what I'm saying is, think about it. There can always be a way thought up to counter some form of super power no matter what it is. Hope this and what Happy says helps.