Are there Gay Friendly Rentals in Cuba?

Yes, there are. Most of them are gay owned or independent apartments.
Here it is just an example.

 Border Old Havana - Havana Center| Habana Vieja - Habana Centro.
GALIANO
Bedrooms in an old little palace in Havana Center /Habitaciones en antiguo palacete en Habana Centro.

CUBA GAY FRIENDLY RENTAL
This "palacete" (little palace) from late XIX century is located in one of the most central areas in Havana,Galiano Street, just 100 meters from the Capitolio. It is an old Palace divided into several apartments and in one of them two rooms are rented. Each room has air conditioner, electric fans, private bathroom and fridge. Even though it is located in the center once the guests are inside the building the sound of the street is dimmed and in the rooms no sound at all. Very friendly landlords, possibility of breakfast, economical and central makes this house one of the most popular every year. Price is 25 cuc per per bedroom per night
possibility of an extra bed in the bedrooms.
cubamigos@yahoo.es