KT-1 Woong Bee, PC-7 Mk.II Astra, PC-9 and T-6A

I am starting to get confused in the Pilatus PC-9 versions.

I have spotted two kinds of PC-9 (one with a double-bent fin leading edge, one wtih a straight one), then PC-7 MkII Astra, then T-6A Texan II, and finally, the KT-1 Woong Bee (KT-1B for armed Indonesia version) but I swear they all look just like the Pilatus PC-9, cannot see a tiny little difference.

Anyone has more info than I have? What are the differences, especially PC-7 MkII and KT-1?

Some KT-1 pics included