To swap the 700R4/NP208 into the M1028 you would need a 6.2 TV cable bracket and a diesel torque converter. You will probably have to change the flexplate. I think the 700R4 uses the small patern.
To swap the TH400/NP205 into your blazer, you would need a gas torque converter, a gas modulator gear and the kick down switch off of the accelerator pedal of the M1028. Some gas flexplates have dual patern flexplates. If yours only has the small one you will have to switch to a large patern flex plate.