The 97 sockets are easy to get, they are Tyco 70/40 series, I have bought them to make Megasquirt adapters.
i read a few years back what the 99 series plugs were, I would need to rummage through my notes. Someone was making adapter harnesses a few years back, I have not kept up to date on this.
P,R,N connector is for idle up. The ECU will not care if that is open.

Is that $125 for the socket or the full adapter?

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.