If space allows, a proper changing table rather than a pull down one would be my preference. My daughter freaks out when she is on one of those that are attached to the wall and pull down, and they are often too small for a toddler. They are often a stupid curved shape and I find them awkward to use.
Even a changing mat on a space by the sink would be fine. Some people are scruffy and leave traces of poo on them, so maybe leave some antibacterial spray and paper towels so people can give them a wipe before/after!
Not in a designated disabled/accessible loo as I feel guilty being in there incase an adult needing the toilet has to wait.
Definitely one accessible to women and men, or one in each loo.
Nothing pisses me off more than sending my husband off to do a change (I am a SAHP so it's a rarity I get to eat lunch out in peace without a trip to the changing room) and him coming back and me having to go because he can't access changing facilities.
It's worse when he is out alone with her and has to do it on a loo seat or somewhere equally gross. I don't understand why it wouldn't be considered to give men the same facilities!