A) Select is a scheme to keep the older equipment as upto date as possible. Castle via the Merlin project are the future.
B) Sooner or later Microdigital are going to have to "wake up and smell the coffee". The 26bit processor that the Omega is based on are no longer manufactured, ArmTwister was a nice idea, but it they cannot get it to work. They are going to have to make the Omega an XScale based RISC OS 5 machine. So, there really is no point in furthering Select for the Omega.
C/D) Select will survive in the short term, in fact it serves a vital function because there are so many 26bit machines out there. Eventually it will wither when these machines are replaced.