Wow. That was a lot to digest. To answer the initial question.

1. The car will run like crap with the big turbo on the stock engine. End of story. If you want to use it for mock up, put an empty block and a head in the car with manifolds etc and build off that for charge pipes etc.

2. no sense trying to learn to tune on a combination that will never run properly?

3. as others have said, the 3082 is Just not a good combo for our engines. a 3071 is ideal for a 2.2 road race car. It will make your goal number when turned up and spool fast when coming out of a corner. 3076 would be ok too but will spool slightly slower.
If you want maximize the efficiency of any of these turbos, whatever one you order should have a v-band flange hot side Plummed directly to a 3.5” down pipe and use the supplied boss on the TU header for a external wastegate. No more swing valves disrupting flow and causing boost control issues.

4. As others have said, considering your goals, you are realistically adding quite a bit of complexity to the build especially intake wise. The established currently available intake setups will allow you to reach your goals without reinvention.

Good luck.