Common misconception, but no. It is 4-pole.
Well yes, but that’s exactly my point. By taking things that have been done before and using those, you arrive at new things. The development of the TB-303 did not happen in isolation.
IMHO the TB-303 is interesting exactly because the people at Roland tried to make a small bass synth with an integrated step sequencers as simple and as cheaply as possible.
The reason the glide has the same duration regardless of the pitch difference is simply because that’s easier to implement.
EDIT: Oh, and I don’t see what’s special or unique about the accents. Routing velocity to both amp and env had been done plenty of times before and is a rather obvious thing to do if you’re trying to emulate how a bass guitar is played.