90 4runner 3vze

Last year I swapped motors from a wrecked 1995 4Runner 3vze. The swap included all accessories attached to the motor. Being in a hurry we didnÆt hook up the A/C as the hoses didnÆt match the pin configuration on the new compressor. As summer approaches IÆm starting to miss the old A/C. The compressor is 134a only the old one was R12. I have several questions and welcome any advice.

1: Can I remove the pins on the compressor so the old hose will fit?
2: Do I need to place or add oil in the compressor? How much? What type?
3: Is it necessary to change the o-rings. What type?
4: Anything else I need to address to get this done?

Thanks All.