common source bias corners
Ok.
"arbitary transistor arrangement"? Not of course It's analog design. Currents in biasing network must be some portion of currents flowing in OPAMP branches. With same ratio the transitors differ. Some transitors for biasing cascode transisitors should be at least 4 times less (difficult indicate at picture). U can read about this in any book for beginers.
Thera isn't bandgap at picture u've been mistaken. But if u need constant GBW i think for diff.pair operated in weak region the PTAT current source is right (GBW=Gm/Cc, Gm=Id/n*Vt, Id=(Ut/R)*ln(N) - PTAT current, where Ut=k*T/q).
1mOhm presistors added only to mix nets with different names.
This is single ended OTA part of comparator. I give it for you only as example.