1) The sky past the atmosphere is not reality-anchored, so go nuts.
2) No, everything does not have immutability, but you'd have to get past the atmosphere, which IS immutable by anyone except me and the Elementals.
3) Everything is reality anchored by me, but I set limits on it, allowing the effects of me, various other superhumans and mages to work within. However, in order for your power to affect any of it, again, you'd have to get clearance, which you don't have.
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)