When considering vaccines, consider, also, that there is no guarantee your kitties will not escape their harnesses or even out the door of your home or car and past you.
I keep Quasar vaccinated for rabies and everything but leukemia, since this was excluded in his kitten contract AND my vet does not recommend it for our situation and location.
Quasar has escaped out the door a few times but he has never gone very far and we have always been able to catch him, so far. The escapes include one time that DH went to work while I was at work and accidentally did not fully latch the back door. I came home to an open door and a missing cat. Fortunately, he was out in the backyard running around like a maniac and came to the door as soon as I shook a box containing some dog kibble, his personal vice.
He also escaped his harness once, while we were sitting in the lobby of a hotel. He ran into a nearby banquet hall, much to my embarrassment and to much amusement of those attending an event in that room.
Enjoy your kitties. Get them out and about. Keep them healthy and safe.