FWIW, I talked to a family of firearms instructors, Angie and Brian Houck, and they strongly recommend, in a blended LH/RH household, that all the guns be righties, because in a SHTF scenario, if someone needs to pick up a dropped firearm, they can use it, because it hasn't been converted to LH (or if they are a righty and can't run a LH, etc). This was specifically tailored towards mag releases on Glocks, but I have used it in all other scenarios. Junior shoots RH long guns left handed. He was raised that way, in case someday he needs to grab one quickly.
I understand that this discussion was mainly about ambi, and I love ambi, my AR is slowly becoming ambi, but he's learning on it RH.
In case of SHTF, I'll be reaching for the poncho. I have no desire to be covered in poo.
After many decades of practice, I'm not too worried about forgetting all that muscle memory of shooting righty. I plan on just learning the controls from both sides. Besides, shooting most long guns left or right should be based on eye dominance, not hand dominance. I can get away with it on bolt action, where I can close an eye. Really hard on shotguns, etc, where you really should be shooting both eyes open.