There’s only one place in WDW where they could make a major screw up by putting a wheelchair on a second floor...
It’s at Caribbean...the only place built prior to ADA That’s not compliant.
Other than that...any other rooms technically meet the fire codes and they can’t technically assign a “wrong” room.
Beyond that...Disney hotels only pay room service to requests...and that’s it. You often can get what you request...but then only internal policy to room control is: don’t lockout any rooms...aka make sure the puzzle fits together...
That puzzle that is nothing like a cruises ship where all days are the same.
You can fax/call/send carrier pigeons...but the reality is they fit the puzzle together first and if that doesn’t work...requests go.
It’s been that way for 30 years...at a minimum. Revenue is first. If you don’t make it, it’s audited daily and explanations are required up the chain.