5 speed swap question

I am in middle of another 5 spd swap. Car is still in the air and the 5 spd trans and axles are installed. I noticed even when the trans is in gear that I can still easily spin the wheels which is making me wonder if the trans is shot. Thoughts as to what would allow me to easily spin the wheels even when car is in gear? Hoping this is normal but pretty sure it is not.

Second question: Wife would like me to thin the collection and as much as I like these cars I am thinking if this 5 spd trans is junk I should just part out the car (adding to my stock of spare parts) as I have 3 other 7g all in better cosmetic condition. I know of a 1998 with a bad motor. Motor in the car I am doing the swap in is good so I am wondering if I can just drop the 7g a (1995) engine in a 7g b (1998) model? Any wiring or other concerns with this? Thoughts?

open diffs will spin by hand with very little resistance. IIRC the two main differences are the distributor and alternator.
1. Just use the B alternator.
2. Use the B dizzy and swap over crank sensor or use the A dizzy and wire the crank signal wire from it to just before it penetrates the timing cover on the B harness.

Thanks for the advice. As soon as I get home I will finish putting it back together and hope for the best.

Got home and put enough things back together/did the wiring to start her to see what happens with the trans. With car still on jack stands the trans works fine except for some grinding when going into reverse. That grinding probably has more to do with the fact I still need to adjust the clutch pedal/clutch master cylinder rod (best info on that as found here: https://www.youtube.com/watch?v=vYJxQyjIhUw ). Looks like it should be fine. The fact I could not spin the wheels with the trans in gear on trans I used for an earlier swap on my 98 7g while I could spin them on this one was really causing me some serious doubts about this trans. Looks like the wife loses out on me thinning the herd for a while longer. Love the knowledge found on this site. Thanks for the help.