1. Dunno if this routing qualifies for STPC (?), where schedule forces an overnight met at carrier expense. BD can advise?
2. The THAI F lounge (actually, any THAI lounge) are closed from around 0100-0500. Arriving on THAI F and transferring to C on THAI metal will allow you access to the F lounge, until it closes. And then when it reopens.
A pain, I agree - and a topic of some discussion.
See here:
http://www.flyertalk.com/forum/thai-...-them-but.html