the idler could be sorted just by running a longer belt and using some maths

the dizzy is sorted as it can run coil pack

as you've sugested, turning the pistons around will sort the running out

oil pump can be electric (or dry sump it)

even the timing issues could be sorted just by having the cps repositioned or electronicly fiddled with

and if there is no dizzy and no oil pump, there is a big puley in the way to use as a make shift tensioner