1. It's safe because finger prints are unique and chance of hackers to imitate it is very low. IMO, the risk that it has using finger prints is that you won't tell it to other people you know personally that you use finger prints as 2FA.
2. 2FA thru authy or google auth are safe. The codes that these two apps generate are changing from time to time and those codes that are shown already expires.
Yes i agree, FingerPrint is very seamless and secure way to login. I would prefer authy or google authenticator rather than using SMS based verification as i saw a post on reddit where a guy got hacked despite he was using SMS as 2FA later it was found that an employee in the telecom company was involved with the hacker to reset/port the victim's sim for few hours so that they can reset his exchange account.