1. Yes, the UL TBF is released OK. When I see CV=0 I send the final PUAN with FBI=1. I don’t do any downlink assignment until I see the PCA for the PUAN.
2. The DL assignment is using CCCH, i.e. either AGCH or PCH depending on what comes first. I set the poll request in the DL assignment and set the TBF start time to be block 0 of the next-plus-one 26-multiframe. (For some reason I seem to get better results if I specify a TBF starting time than if I don’t. Not sure if that’s relevant.)
3. Typically this is in GMM ready state.