My channel has almost achieved "Twitch Affiliate" status - What should I start thinking about and what should I be aware of?

Is there anything I should be concerned/careful about when being Affiliated with Twitch?

Read the legal agreement very carefully. If you're currently employed, make sure that signing the Twitch Affiliate Agreement doesn't go against anything in terms of your current employment and vice-versa.

is their a fun and engaging way I can create some form of "donation goal" without seeming greedy or tacky

You can either be honest about your intentions to improve the stream quality, hence, the sub goal, or you can set a "reward" for achieving said goal (doing a cosplay, giveaway, shaving your head, whatever's your thing).

Can't really comment on your other questions.

/r/Twitch Thread