@Phil---Liz0 Whether you can still ask for proof of vaccination depends on your local laws. But most cases of the current variants are being transmitted by and between vaccinated people, so unfortunately your requirements would be useless to you anyway.
If you can set up your home in such a way that guests have minimal contact with indoor common areas, or have separate entrances and bathrooms, you might be able to pull this off. But if someone in the home faces a major health risk from a possible exposure, I would not under any circumstances recommend continuing to host inside the house. It's just not worth it.