FVRCP is considered a CORE vaccine, yes. Your vet is correct that vaccinating a cat after infection isn't going to help. However, it is currently recommended that cats get the FVRCP and Rabies vaccines yearly. However, vaccinations should be discussed with your vet on an individual cat basis.
As for cleaning, the antibacterial wipes are not recommended for use on food surfaces,...their instructions recommend to thoroughly wash any eating surface if the wipes are used. Really, nothing beats good old fashion soap and water. This is why I recommended paper plates/bowls while you get the situation under control.
As for the water tank...I think the only problem would be backwash. Pet haps poor some of the water out before flipping the tank upside down to remove the bowl could help safe some water?
As for cleaning, the antibacterial wipes are not recommended for use on food surfaces,...their instructions recommend to thoroughly wash any eating surface if the wipes are used. Really, nothing beats good old fashion soap and water. This is why I recommended paper plates/bowls while you get the situation under control.
As for the water tank...I think the only problem would be backwash. Pet haps poor some of the water out before flipping the tank upside down to remove the bowl could help safe some water?