Dear Nikhil,
I’ve done a similar project and its working fine.
You are only receiving from gsm and finger print module. Also the finger print module is using less frequenly compared to gsm. You can switch the data coming from the two modules into a single uart using analog switch IC like cd4066. Its all about taking the data from only that module which is required at that particular moment. Additional coding and circuitary required to control the switch.