Do agented manuscripts get preferential treatment over requested slushie ones?Not unless the agent's doing a better job of nagging me, or has let me know there's interest elsewhere and he/she needs an answer by X date. So the practical answer is yes, sometimes. But not because I think agented manuscripts are better than ones I've requested.
How often do you have editorial meetings?You mean acquisition meetings? This varies a great deal from publisher to publisher. Could be weekly, could be monthly, could be whenever the editor has a chat with the boss.
Do you tell a writer that a manuscript went to a meeting before, after or never?Any of the three. I'm not picky. Do you want to know before, after, or never?
Do you ever ask for revisions before making an offer?Yes. I don't think it's fair to ask for more than one without a commitment on the table, but yes, sometimes I think I see something in a manuscript that I'm worried the acquisitions group won't, so I'll ask for a rewrite. This is also a test: the good writers are the ones who are good at rewriting. Some people are only good at first drafts, or terrible at using feedback effectively, and I'd like to know that about someone before I commit to working with them for months/years and spending many thousands of dollars on their project.
If you do ask for revisions or offer to look at something after a revision, do you think about that manuscript or is it out of sight, out of mind until it lands on your desk?Out of sight, out of mind. And often out of memory. As in, it comes back and I have to work to remember what the project was, why I was excited about it, etc. This is not a reflection on your manuscript. This is just a fact of the publishing office. It's a high-distraction, sometimes high-stress environment.