“Do hotel room stays qualify for the California renter's credit if the overall time spent there is six months or longer?”====I don’t think so.To qualify the credit,. You must have paid rent for at least half of the previous year for property that was your principal legal residence. I guess you need to rent a home or apartment in CA; you can contact the CA franchise tax board for more info in detail; https://www.ftb.ca.gov/aboutFTB/cont...tility_Contact
“Or do the stays in combination with other standard house/apartment rentals fulfill the six months requirement?”===== It is possible to receive this credit even if you did not not live in a rented unit for the entirety of the year, so long as you lived there more than six months. People who are receiving money through the Renter Assistance Program are also still eligible to get the CA Renters Credit as long as they qualify in all other ways.