Sounds like you want a earlier 70-79 Standard model. I actually really like my 80 special with those buck horn handlebars, I found them real comfortable.
Anyway, if your going to switch to shorter bars your going to have a lot of slack with the cables and hoses. Wiring loops easy enough in the bucket, but you'll have to get creative with the throttle, clutch, and brake hose or you'll have some pretty big loops popping out. Shorter cables and hoses from anything 76-79 will work.
As for the wheels, that rear mag has a disk brake. Other spoke wheels will swap out, but only those mags had the disk. You would also have to swap out the swing arm and some brake parts too to go with spoke wheels. The front will be a direct swap.
There's a lot of seats out there. You might be able to get the look your going for by getting an earlier seat cover, and shaping the the foam down. That way you don't have to cut any tabs off your frame.