1) Uhm, you have problems getting it booted from CD :P It's weird that it won't boot from it from alt-menu either..

2) & 3) There's recent thread about that https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9541&forum=11 although I don't know how well that Chrysalis works in that case. Probably ok, but make backup just in case.

4) I'd change it after the installation so that you'll have the latest drivers installed, but basically if card is supported in both versions, it doesn't matter in which order you do it.