Based on your past experience, you would seem an ideal candidate for a build. The build school would be a good experience. You'll see first hand what it takes and if you're up for it. But may not be mandatory. Your choice. One of the big variables is how closely you stay to proven and supported choices (engine, trans, suspension, wheels, etc.) and how much customization you do. Keeping it close to the Factory Five recipe helps insure success especially for new or inexperienced builders. For $10 you can order and download a build manual on Factory Five's parts website. That's a great way to learn more details about a build.
Do you know about the London Cobra Show? (
https://www.londoncobrashow.com/) It's practically in your back yard, only a few months away (hopefully not to be delayed or cancelled...), and would be a great opportunity to see lots of builds and talk to owners.
Regarding your build, I'm a huge fan of the Coyote in these builds. I've done a couple and they're excellent. Regarding your potential configuration, I'd question A/C unless you're planning to add a top. I know guys in the much warmer south sometimes add it and say it's helps. But for the midwest, I just don't think it warrants the added complication. My weather here in SE Michigan is probably very similar to yours and there are very few times I think it would have really been useful. But then I didn't even put heaters in my Roadster builds. Just heated seats and that got the job done. So consider the source.
You don't mention transmission. The new TKX would be an excellent choice. If you want a 6-speed, the T-56 will fit with IRS. But it's more expensive and a bit more complicated to install. Your 50K budget is probably about right for a higher end build like you're describing. For parts anyway, especially if you use all new. The one variable that catches a lot of builds is body and paint. The price for that is all over the place, from DIY to high end custom shops.
My 20th Anniversary Roadster build configuration was very similar to what you're describing. Build thread with lots of details linking in my sig line below. That build was a few years ago now, and some of the information is starting to get a little dated. But still may be helpful.
Don't know what your timing is. But just FYI, Factory Five is slammed with orders right now. Promise dates are in the 5-6 month range the last I heard. Plus, like the automotive supply chain in general, are experiencing some challenges with backordered parts. It will all work out. But will take time and patience.
Welcome and enjoy the ride.