I would not be so quick to dismiss the heat side. I've not seen a mini-split that does not heat as well, and they are getting to where they work down near absolute zero (well maybe not that low). I get the "gas heat, gas stove, gas, hwh, gas from beans, (er... too much blazing saddles)", but my problem with it is, now you have to buy gas. Now some of the folks here were talking propane at $0.50/gal. Ok then for now that's sort of a no-brainer, but personally I adore my induction cooktop, and despise gas ovens. If you can just build out your solar to handle it why buy gas? I'd probably build a ranch, not a 2-story and dig it in. You will probably do whatever your teenage bride likes
. The in-floor / pex stuff is pretty good/efficient. Make sure you engineer multiple redundant loops with some bypass manifolds. They do sometimes fail, ( and floor cores suck ) and I'd look at a dual electric/gas heating system for it. Same thing for your HWH.
The thought crossed my mind you could put in both a tank for electric, and a gas demand hot water. Pass the electric heated water thru the demand system, put a sensor with a short delay and turn on the demand system if the electric is not pushing hot water. DIY dual setup. Lather, rinse repeat for the in-floor setup, if you can't find something that already does something similar. Of course, if you have the solar, it's bloody silly not to use it, but when it turns to sh*t, your gonna be using gas anyway, likely at some point to run a genny as well so. . .
Maybe split out to two panels a true "critical loads" panel for all the critical loads (Lighting, fridge, gas system controls, etc), and a high load panel for mini-splits, electric heating stuff, the EV you are not going to buy, whatever eats it up. The High load panel de-energizes with say 40% SOC on the batteries, depending on how agressive you get with battery purchases. The critical panel stays hot all the time, and the inverters turn on the generator as the SOC drops to 15% or something, let it charge the batteries to 30% and turn off (Below the high load cutoff) , keeping the lights on, and all the controls working. I think the EG4's also support generator assist now, so you you don't have to buy a ridiculous generator, just something that is a little beefier than your average usage on the critical panel. I think all that is doable with minimal fuss, and won't really break the checkbook either.
I hope it all goes well for you, be sure to keep us posted.