You can take some solace in the fact that a very high percentage of cats have been exposed to the corona virus and never go on to develop FIP.
Most just get the URI symptoms, then their immune system kicks in and most often, along with some Veterinary intervention, they get better. In a small...
The short answer to your question about whether a kitten at generation F3 can be born as a wildcat is no. It is a hybrid with diluted wild blood and is considered a bengal and registered as a bengal.
It is extremely unusual for a third generation bengal kitten to look exactly like an Asian...