First, evaluate the risk of these illnesses for your cat. Feline leukemia virus needs direct contact to spread to another cat. FIP is not very common in single cat households and neither are the other viral illnesses, for that matter. Cats that are interacting with other cats are more susceptible to all of these conditions and situations in which cats and kittens mingle seem to be the most ripe for viral shedding. Rabies vaccination is required by law in most states.
Adult cats are highly resistant to feline leukemia virus, in most cases.
We do not recommend feline leukemia vaccination for indoor only cats. So it would be easy for me to eliminate this potential cause. Feline infectious peritonitis virus vaccination does not appear to be highly efficacious, to me, and there is some evidence to suggest that vaccine induced FIP infections have occurred, rarely. Indoor only cats are not likely to be infected. We have not used this vaccine in our practice for several years.