Engine swap Kohler to Briggs?

[Craftsman Garage]

I have a Kohler courage pro sv735-0016 on a craftsman dgs6500 (917.288600) that wont work right, very finicky and kicks over a bit with starting fluid. I’m done messing around and wasting my time on a bad engine. So my question is:
1. How easy do you think it would be to swap the engine?
2. Could a Briggs vtwin fit on the existing mounts?
3. Are there any SPECIFIC models that would or wouldn’t fit? (I’m probably going to swap to the newer style V shape ones, not the 90s opposed ones.)
4. Are there any modifications that would need to be made? The wiring harness connector looks the same as a Briggs. It does have a separate choke knob and I know with Briggs twins, thd choke activates when throttle is pushed up all the way. But is there any way I could make that auto choke mechanism work separately?
5. As a last resort, and cheaper alternative, if I don’t find a good Briggs twin (USED), could I put a Briggs single on here? I like them and they are great for me because they startup quick! Thanks!

 

[Forest#2]

You asked:

1. How easy do you think it would be to swap the engine?

Painful.
The replacement engine will need to have the same dia and length crankshaft stub so as the existing drive and PTO can be used.
Lots of things to consider especially if it's the electric PTO. (even the exhaust system can be a challenge. (trying to save bucks)
I've done such but did not have to buy a replacement donor engine, already had a donor and sometimes hit a surprise stump that no go.

If you can find a IPL for your tractor sometimes they will show alternate engines being used so as to compare parts.