For health insurance, is there a benefit (so to speak) in staying within the former employer, now client's pool, as opposed to shopping independently? I don't know much about this and what is possible. I've heard mention in the past of some people achieving such an arrangement. Whether that information was correct, I am uncertain.
EDIT: I updated my prior comment, above, to better reflect my uncertainty.
yes. it will almost definitely be cheaper in total with your employer (i'm not taking who actually pays -- you, your employer, or both).
going solo, it will be more expensive unless you can get in with a group of some sort. for example, you can join up with the freelancers union and get help with your rates (i think -- haven't actually done the work to see whats cheaper).
EDIT: I updated my prior comment, above, to better reflect my uncertainty.