@Genkai Thanks for clearing all this up. I think acquaintances/distant friends works well because there are opportunities for bonds to develop naturally between the characters. I agree with above statements that it's easy to create an 'outsider' feeling for some people when there are existing histories (especially OOC) which makes it really easy to lose someone's interest. And when you're writing a lot - spending time to think out, write, and polish something creative and interesting that is focused on building the story and developing characters, losing interest is a killer. If people are going to put forth the effort to write, it's important that they feel included in the story.
At least 1/wk works just fine for me. I am employed full time and in grad school (fml) but I should definitely be able to make this commitment, maybe even be a little more active if everyone else is moving quickly. I agree that 2/wk is pretty quick and anything more dilutes the quality of my writing. Some people might be able to keep up with that, but I'm not one of them.
One last little bit about the pre-gen classes/original classes/curated classes dilemma. For me, none of these are deal breakers or even really annoyances. The deal breaker for me is when people don't collaborate/cooperate.
@Everyone I'm looking forward to writing with you!