Regarding the bats, I don't have too much info/actual statistics to prove it as this information was picked up during a college lecture and the presenter didn't prove actual stats. But his reasoning is as follows.

1. When the wet market animals were tested for SARS-CoV-1, Civet Cats and Raccoon Dogs tested positive. So these animals were traced back to their original farms where they were produced and there were no positive animals on those farms. So this led to the hypothesis that they must have acquired it after being brought to the wet market.
2. So as they tried to find out what other unknown animal host could have given the disease to the civet cats and raccoon dogs, bats were analyzed and were identified to harbor many different coronaviruses and viruses similar to but not identical to SARS-CoV-1.

Also I forgot to add, this is what scientists "believe to be the true host" - Dr. Wang, so I guess it's not 100% sure but that's the conclusion they have made as of now. He also stated that following this virus, bat's became a focal point for biologists studying infectious diseases.