Correct, B&T makes the MP9. They bought the TMP design from Steyr. Cosmetically the only main difference is the addition of a folding stock and some changes to the fire selector I think.
KSC/KWA make an MP9 currently on their new NS2 system. KSC also made an old MP9 on the NS1 system. Before that KSC had a Steyr TMP and Steyr SPP model, but both werent suited for propane use. The NS1 MP9 was reinforced to handle the higher pressure, whereas the NS2 models are built for propane use.
KSC makes a suppressor for the MP9. Its a custom quick-detach design since the flash hider on the MP9 isnt threaded. Theyre impossible to find.though. Most people just fabricate their own, or modify the flash hider to accept regular threaded suppressors
H&K G36c (KWA) / Glock 18c (TM) / Kimber LAPD SWAT Custom (TM) / Mossberg M500 (ACM)