You can draft ONLY a limited amount of times a day from any HC.
A 12 HC can draft 4 times a day (changes on reset of server so you can get lucky if evony messes up and has multiple resets).
A HC can draft any city OR NPC within a certain radious, I think Satan has a good guide on ranges somewhere. 8 miles north south east and west at least. corners are further.
You can draft multiple times from one npc city. Npcs will not REGEN until server reset for drafting (different to attacking it). So first draft of a lv.10 npc gives 40k warriors, next gives 36K warriors and so forth.
If you are a suzerain of a city near a 12 you also hold you can draft from the colony as well, so you can draft it a lot. But its 10% of whats there each time, not a constant 10%, so you cannot draft 40% of a city's best troops, you draft 10% of 100% of a branch of troops at the time of the draft, then 10% of 90% (9%) of the original amount, then 10% of 81% (8.1%) of the original amount and so forth.
I am not sure if you can draft a player using the 12s multiple times, but I cannot see why not.
Scythe on S3, W12, etc.
Scyther S128 Retired..
Scythe NA4 Retired..
RuinUrDay S146 (Retired).
+REP me if I helped you.