I'm mostly concerned with the Q1, because once I get something published - it's locked even from myself. There are some papers I wrote, but I only have "Proof Version", and I have never seen the final version. In other words, it looks like I gave them all the rights.
Concerning the Open Access, warning for the authors, although it an Open access, there are still several sub-types:
- "do whatever you want"
- "only non-commercial"
- "ok but don't change it"
- "ok, but it must stay under the same license"
And the combinations of all 4 previously mentioned cases
So, those symbols are ok: 
and I suppose this one, but it's little grey (SA - share-alike): 
This is very grey as SteemIt is sort of commercial: 
I have no idea if it's ND (is direct screenshot a derivative or "original")
So, what's the final agreement after the post by @mobbs ?
I, personally, stay away from NC because I see steemit as a form of profit. SA is okay as long as proper attribution is given (many do not do this which is the main reason why this bot is created as many do not do the proper attribution.
I do not know the proper answer to say for question 1 (mobbs did go through the difference between SA, NC, CC0, etc)
Noncommercial is specifically related to making money from something, so in our case unless we choose to deny upvotes from our post, we shouldn't use them. UNLESS we ask permission. Email would count as evidence if they for whatever reason changed their minds.
I've emailed many scientists saying how I expect to make a certain amount of money from it and they've always welcomed it and expressed interest in seeing the final post. This is the best way to bypass the restrictions of law.
Regarding giving the rights to others, yes it would be like selling your rights to others but unless it's written in contract form with your signature it has little meaning and thus you basically still hold the original form - which is yours.
There's a lot of in depth answers you can explore in the USA FAQ which should clarify most things