I listened to the press conference, and I didn't hear anything about imported frozen bats. I heard them say that wild animals that are known to be susceptible to SARS-CoV-2 from Yunnan province, where bats are known to harbor coronaviruses similar to SARS-CoV-2, were shipped to Wuhan, sometimes frozen. They want to look into those supply chains. Fomite transmission is something that's widely acknowledged to play a small role in SARS-CoV-2 transmission (it's why you hear recommendations to wash your hands and avoid touching your face). If wild animals (both living and frozen) that can carry this virus were shipped to Wuhan from a region in which wildlife harbors the virus, then that's something that's worth following up on.

About the lab, as they said in the press conference, no lab in Wuhan (or anywhere else in the world) had any samples of SARS-CoV-2 before the pandemic began. A virus can't leak from a lab if it's not in the lab to begin with. The closest viruses anyone has found are 4-5% different from SARS-CoV-2. The discovery of a new one was announced in the journal Nature Communications just yesterday. With enough wildlife sampling, SARS-CoV-2 will eventually be found in the wild. But it may take a long time - bats are strongly suspected of being the reservoir for Ebola, but I don't think anyone has actually found a bat in the wild with an active Ebola infection yet, in decades of searching.