So please correct me if I'm wrong, but the early FWD impreza/legacys had the same spline count as the ea71 wagon.
So would it basically be just a drop in and hook up scenario, besides obvious ej swap spoob (wiring, fuel lines, ect.)?

Yes.

 

Shifter would need to be modified.

 

May even take swapping pedal box to get a clutch cable that works, may not.....not familiar with 1st gen swaps just second gen.

Aside from the spammy spammer post.

 

You'll have to "massage" the frame rails for the ej22 to fit, otherwise the valve covers will not clear. Not sure exactly what you will have to do with the pedal box, but my ea81 did need some mods to use the correct cable with my ej trans.