And the water heater could be in a more optimum place -- right above or beside the home air handler so that the cold air coming from the water heater doesn't gain much heat (lose it's coldness) before that free cold air is distributed through the house.
Another thing I could have done when I replaced my shingle roof with a metal roof a decade ago (before I thought about going solar and getting a hybrid water heater) was get a dark colored roof so that the attic would get even hotter in the sun and give me more free hot air in the attic, perhaps even in the winter, for the hybrid water heater. Even with most of the south-facing half of the roof covered with solar panels as well as some of the north-facing roof as well (the portion of the roof that's practically flat over the porch), I bet there's still enough surface area of the roof getting direct sunlight for which a darker colored roof would have given me more free heat in the attic.
Now that LED lights look good, almost all light fixtures would be LED (not enough savings IMHO to replace old light fixtures in my existing house). Especially now that there are DIM switches for LED's.
If I build a house from scratch almost every room in the house would have at least one 120V outlet that's intermittently powered with free solar like the 240V intermittent outlet we do most of our EV charging with. Think about all of the battery powered tooth brushes, razors, etc. that don't have to be charged every day -- you'd usually be satisfied charging them only on days that have free solar power. I have 120V outlets in my garage like that (my garage was outlet poor, so when I hired the electrician to install the two 240V outlets for the EV, I had him install a handful of 120V outlets in the garage and outside, half of which are intermittently powered). So every time I'm done with my hard work, my battery yard tools like my weed trimmer and blower, are done for a week. Thus, I put those batteries on chargers that are plugged into intermittent 120V outlets (who cares when they get charged, I'll have free solar to charge them by the next grass cutting day). The same with the EGO battery riding mower I just bought (my old John Deere went kaputs a couple of weeks ago). I cut our grass Saturday and my mother's grass Sunday, then after that I charged four 56V/10.0Ah batteries in the mower sometime this week on the intermittent outlet by the shed (though there's a constant powered outlet if I need an immediate charge regardless of if power is free). The mower's batteries are charged to 100% now for this weekend without me caring when it got charged (because I didn't need it for a week between grass cuts). Those random charging of battery powered tools aren't enough to warrant the expense of adding intermittent outlets unless you don't have outlets in those places anyway and are spending the expense to install the usual constant powered ones (might as well spend a little extra while the electrician is there for the intermittent ones). Thus it'd be optimum to do that at construction time, and do it throughout much of the house for our ever increasing battery powered devices.
Sounds like good ideas. Unfortunately, many people have to simply do the best they can with retrofitting, and they can only go as far as is practical.