Yes, absolutely.
As regards nomination races, people can legally buy memberships for other people, and that's considered as a contribution by them. This procedure already exists, although I find it somewhat bizarre. I believe this arrangement can be used to enable a 12-year-old to become a member of a party because, in general, 12-year-olds don't have enough income on their own.
I believe there are ways to resolve the membership issue and to establish sensible criteria for those who can contribute, particularly amounts of money, as we've recently seen.