1. It is only affected by enemy units, you can't mimic your own unit's upgrades. If it is WAI, fix the wording. 2. It only gives one upgrade, not both.
The Mimic spell specifically says opposing champions. As for #2; I can DEFINITELY replicate this and it absolutely seems to pick a single upgrade, almost 75% of the time. I'd say one of four or five times does it actually give both abilities, which makes this way worse.
Incorrect. "Target friendly champion gains all upgraded abilities of adjacent non-Avatar/Boss/Elite champion. Basic attacks and abilities that change a champion's form are not gained."
You're right. For some reason I assumed it was enemy-only; but now I don't have any clue why I thought that. I just know I've thought to myself multiple times, "Too bad I can't put friendly upgrades on this guy".