Sounds like a very interesting project; I hope someone here has specific/verifiable information for you. I look forward to seeing the final painting in the calendar. Always good to see you in the TNG forum too.
As a fan that doesn't really follow the technical canon side of things at all closely, on a personal note I think it would be fun if there was some aesthetic/design lineage with the only lifeboats I can recall seeing - the ones in First Contact from the E-E. A precursor variant of these would be good. I always assumed they'd be collected by tractor beam into the rescue ship shuttle bay (or if still under power from their thrusters, land under their own steam in the shuttle bay).
As I say, that's just my gut feeling, and not based on any sort of verifiable canon answer! I'm sure others will be along with more suggestions soon.