as far as the FTEs go... one thing I know of is that some PAPs came with a recoil spring that was too weak. it might be worth a shot to try another spring assy. if you have one available.
punches are usually case hardened, so cutting one down can weaken the impact surface.. just one thought.
I've never had one that I couldn't get a pin out of eventually, so not sure what else to tell you.
one thing I have done on AK pins when demilling parts kits, is to use socket drive torx bits as pushing devices, and use a socket on the other end to catch the pin. I then put the assembly into a bench vise and crank. this will generally push out pins that refuse to budge with even a starter punch and a large hammer.
I would bet you could rig up a similar setup with the AK bolt, putting a small socket on one lug to receive the pin (I might suggest putting a brass washer between the lug and the socket), and placing the torx socket into the pin channel on the other side, pushing the pin out to get it started. you can then finish it out with an appropriate punch..
Here is an example of this method being used on a trunnion barrel pin.. Though I didn't picuture it with a socket on the receiving end, just a brass washer at this point.