THANX, Dennis. I realize - and fully expect - that if I create a profile for her, it will be unlisted until she accepts the invitation to join. Seems like the invitation to join is automatically generated upon entering an email address in a profile, so she should receive that email without a problem and when she accepts, it should automatically change her profile from unlisted to private - or at least give her some kind of message about needing to change it. I'm sure a family member can edit their own privacy level - I can't imagine even a guest member not having full control of their own profile.
The reason I don't want to just give it a try is that if it is something we're not supposed to do under the new rules, I don't want to violate them. As I commented on Dale's answer, I'm looking for an answer that is not the "interpretation" of you, me, Dale, or any other ordinary member - nor a leader, for that matter. This gdpr stuff is serious business and the ramifications of doing anything that would bring down the wrath of the EU on WikiTree is something that has (or certainly has good reason to have) management quaking in their boots. Under these circumstances, I'm near paranoid about being careful to stay well within the rules they established for their margin of safety.