Not an answer, sorry.... I too anticipate a future advanced toilet and was wondering which side of the toilet we should put the electrical outlet? Is there a standard or typical side, left or right when facing the toilet/wall?
Any more tips or advice in planning for a future install?

Some brands have the power cord on the left, some of the right. The cords are usually a few feet long so they can loop behind to get to the other side if need be.

Other than that, as you wrote it's simply a matter of making sure the top will fit the toilet. Most "standard" toilets are fine. It's the curved tanks and sometimes the one-piece toilets where issues can arise.

Your safest bet really is to print out the "fitment pdf" for the advanced seat you're getting and compare it to the dimensioned spec sheet for your proposed toilet. There are usually just a few measurements you need to be concerned with; the bolt hole spread, the tank-to-bolt hole distance, and the tank to the inside of the front rim distance.

Some advanced seats have manual controls on the right side (when sitting) back by your hip. If you're getting one like that, just make sure you have elbow room to manipulate the controls. Normally not a problem. Personally, I prefer the handheld remote. If you have one with a remote, they usually have a mounting bracket to hang the remote on the wall, or to press the buttons when the remote is in the wall bracket.

Great question! I was thinking of having an outlet installed too. Turns out the one in the kitchen on the powder room wall needs to be turned around into the bathroom anyway so it's not behind the oven. Happy accident! It will be a little above the tank, so visible, but short of rerunning all the wire in/out of it it is what it is. Just hoping if we ever take the plunge it will work.

Do keep us updated on anything helpful you find out!

guess you will need to clean that remote also, unless it has an antimicrobial feature)

You will need a dedicated circuit for the bidet function of the seat or toilet. It doesn't share. Make sure you have room in your electrical panel for that.

BIG RED FLAG You cannot "turn" an outlet serving another room to become an outlet in the bath.

You cannot use either of the two 20 amp required kitchen small appliance circuits anywhere but in the kitchen. It cannot serve any other room. If it is in the way of your proposed design, you must remove it. And you cannot have a junction box behind the oven. You have to trace the wires all the way to the attic or another accessible spot if you need to do a junction box to continue the circuit around the room. Otherwise if it is the "end" of the circuit, you can simply eliminate the wire to that outlet from the previous outlet served by that circuit.

Thanks, Hollysprings, I will have to ask again. I may have misunderstood. Maybe the plan was to remove the outlet, which is not needed and just leave the junction box with a blank cover accessible from the bath? It's the start of one of the circuits and the wiring was originally done only half right so we have to sort out a lot of things. And as a bonus, they left zero extra wire there, so we don't have any slack to move it over, it needs new wires from the box and to the next outlet if moved.

I did upgrade my box ahead of this project, thanks for checking. We were out of slots and I knew I needed at a minimum a new dedicated line for the new oven, and likely more than that.

monogoct and hollysprings... exactly the type of information I need. Thanks so much!

(doubt the panel has room for a third new dedicated 20 amp - drat)