71 scamp build, need direction

Just picked up a 1971 Scamp 225.

What I would like to accomplish:

Extremely well handling (planning on the Hotchkis TVS with 18 inch wheels)
Mildy quick 225 while still retaining decent mpg
Possibly disc up front or all the way around

I am pretty sure the 225 models came with the small bolt pattern and the 7.25 rear. Looks like I need to think the brakes through before I get wheels, right? I would like to avoid spacers.

Will disc change my bolt pattern size and wheel spacing if i buy a kit?
Is the 7.25 rear ok for an enhanced 225?
Will the 7.25 accommodate rear disc or do I need to go to a different rear end?

Thanks!