So glad I started this! I have been following but haven’t had time to quote/cut/paste/reply as I wanted to.
Lots of good ideas I hadn’t considered, also some good feedback that a lot of what we have planned is on the right track. And a couple things we deleted 
Hope you’ll forgive me if I make a list instead of replying to your particular post or failing to giving you specific credit for your ideas 
Let’s see…'lectrical.
Lights: I had a religious moment at the Depot this week when I realized there are 4" LED recessed lights that are not only dimmable, but you can control the color temperature of the light. And, you can do this from either a wall-mounted panel, or an app on your freaking phone. Or you can tell Alexa to do it. I am still not sure I’m mentally prepared to process that. I’m not saying I’m doing it, at $60 per light x 6 lights…but I’m not saying I’m not, either. If I do, I’ll have separately controlled lights in the shower ceiling and the bathroom proper. No matter what, I am pretty sure I’ll do lots of recessed LED lights even if they’re not the fancy ones.
Wife wants a giant mirror, and lots of light above it. So she gets a 3’ wide mirror, and a 5- or 6-globe light vanity mirror above in addition.
I’m wiring to the right of the sink for a wall-mounted hair dryer, hotel-style, which takes up a space but also alleviates worrying about where to plug it in.
Regular old receptacle to the left of the sink, and a dimmer switch for the vanity light. I love the idea just a few posts ago to put a receptacle right behind a shelf for charging shavers etc. We’re nor sure which cabinet we’re using yet, but a proximal outlet for chargers will be included.
And you bidet people have me convinced. I added a bidet seat on the budget spreadsheet and I’ll wire a recep for it as well.
Heat…my wife is always cold, so she requested heated floors. I don’t think I’ll do tile, since that would be one thing I’ve no experience with and don’t want a crap tile job. I am pretty impressed with the vinyl laminate material, and there are good heating solutions to go under those. Also, I’m going to add a small wall-mounted heater between the commode and vanity to keep the room warm even at night when the furnace isn’t running.
Skylight. Man, I really do want one, and it’s only about 2-3’ to the roof. One of the ducted skylights would be awesome and I had brought it up, but the fact is we just don’t spend much daylight time in there. It’s not ‘on’ or ‘off’ my mental version of the list, though.
Grab bars:
Came up so many times, and I’m glad it did. I probably will not actually install them yet, but I will absolutely be installing blocking and taking note of the location for the future. I can also see where they definitely would have been handy a few times in the past, but when the day or event comes that they are necessary, they can be put up in no time, and be sturdier than if they were anchored in wallboard.
Eh, I won’t bore you guys with every little detail. Just realized this post could get awfully long
This project, as I said in the OP, is major project #2, and before major project #1 begins, there are a few project #0.1, #0.3, etc. that need to be completely closed out. This will probably start demo in the late summer/early fall.
Thanks for the ideas!
Ok, shoot, last thing…as Spiderman indicated, I’m tall and stuff. So the other requirement is a frameless glass door tall enough for me to step in to (won’t be a glass surround(!!), since the shower is walled on 3 sides) with a glass bulkhead panel above. AND an overhead rain shower, and hand-held shower tall enough for me to get my head under without bending over. The logistics of meeting that requirement, while also allowing my wife to access the head without pulling it down by the hose, have yet to be worked out.