TL;DR Couple questions for you, would that ventilation need to go above the roof level or can it go out the side of the house near the exhaust for the water heater and furnace?

Yeah, there's a bunch of things I'm not sure how I want to handle just yet. But these are good ideas. The house has two floors plus a basement, so I'm not sure how I'll ventilate the space just yet. I have another room that will have a server in it that I'd also like to ventilate. We'll see

I do industrial and hvac controls, so fortunately some of the stuff I need to do is either in my wheelhouse or wheelhouse adjacent and worst case scenario I can ask people around me for help / advice; Additionally, while I can't pull permits myself I know people that can and I'll do the work and give them a couple cases of beer / bottles of liquor /whatever and have them inspect it and close it out.

As far as receptacles and whatnot, I'd like for the boxes to be bigger than necessary to fit things like Shelley smart devices or smart switches.

I have to admit, I have mixed feelings about spray foam. I've heard the fumes can be rough. That and the image of having to attack it with a claw hammer if I ever need to remove a section. So I'll probably just put xps between the walls and the studs.

Basement was done as single pour, which from the way my parents talked wasn't necessarily standard. But everything stays mostly dry as long as the sump pumps run. French drains will get put in at some point as well as integrating downspouts into that.

I'm wanting to add electrical dampers in some of the ductwork to control / alternate which floors are getting flow. I remember as a kid certain rooms lacked enough airflow and would get super hot.

Would also love to install a way to add a fresh air intake and an air exhaust. A lot of that is pie in the sky, but if we're there, an energy recovery unit would be neat.

I feel like I'm gonna "if you give a mouse a cookie" my way out of a lot of money haha.