* Is there a sticky explaining the differences of airdrops vs bounties vs signature campaigns?
None but if you can create much better.
* Do they favor my status (Jr Member I think I am) ... I know that higher statuses earn more at this point
As long as your eligible, low or high rank are equal.
* Can you participate in more than one?
Signature bounty, no. I haven't seen a member two signatures at the same time.
But signature + airdrop + social media campaign is possible at least ( I guess).
* If you post here everyday as a habit, what's the level of extra effort involved in participating in bounties and signature campaigns?
You converse normally and you are not forced to post because of your campaign.