I have built "Winstad Manor" AND have a Child's Bed.

But any child I want to adopt still comes up with the ....'no room' in conversation dialog. This is with ANY of the adaptable children.

This should NOT work this way. I should NOT have to buy a Child's Bedroom if I already have one.

Is there a console command that will remove the requirement to buy a Child's Bedroom

You need more than just a bed.

I don't think you need every item in the room to be built, but I know a bed, chest and dresser are needed.