Depending on what is in the jeep for a trans, I think I would be inclined to start it and leave it in neutral. That way the trans get the needed lubrication.
I used Raptor on the box and grill guard of my RTV, it has been very durable and looks good. BUT, prep is 80% of the job, it will only be as good as the prep work.
It's not sounding good. With the front axle in the air, and the tractor in 4x4 and low range. One wheel should turn in the opposite director of the other. I would not continue to use the tractor even in 2x4.
I would check and see if the front drive shaft is still intact. Redo your test and see...