1) Adepts are Awakened, this is part of Shadowrun for... always

I agree this may have been stated more clearly in Anarchy, but here are a few quotes that show that you need to be awakened to take adept powers:
Adept Powers: Instead of casting spells, adepts use mana to perform physical magic.
If you’re not Awakened, you can’t access mana to do amazing things like cast spells, summon spirits, or enhance your physical abilities.
You can also take a look at Knox character on p. 104: she is awakened and all her shadow amps are adept powers.
It is not clearly stated that when awakened you can take either spells or adept powers or both. My understanding is that if you want to stick to regular shadowrun you can play a mage by selecting only spells or adept by taking only adept power, though nothing prevent you from taking adept powers and spells
2) To be honest I do not really understand what increasing damage when using agility would mean... I would suggest to select either an attribute (and get associated bonus die) or close combat damage increase
3) I would say yes, however the wording is not clear:
Only one Shadow Amp can affect a roll’s outcome; if two or more could apply to the Test, you must choose one effect to apply.
I would argue that the damage increase does not affect the roll's outcome, but this is debatable.