"This is our daughter's boyfriend."
For my father and my mother, "Wo baba" and "Wo mama" can be used. Is not that the case for "Wo nu er" as well?
Generally speaking in a row of 的 modifiers, all but the last 的 is omitted if possible.
我女儿 is correct, it’s probably just not been added to the list of accepted sentences yet. Report it and I’m sure that will be corrected :)