1) If I have the current Beta Application on TestFlight say version 1.0.2 and 1.0.1, I want to upload 1.0.2 to App Store for reviewing. Will this affect the current testing from using the installed beta 1.0.2 version.
2) Once the 1.0.2 version on live (in appStore), will I be able to use testFlight for beta testing in later version say 1.0.3?
Your latest TestFlight build 1.0.2
Previous TestFlight build 1.0.1
and you want to upload 1.0.2 to App Store. In this case Uploading 1.0.2 to App Store won't make any impact on installed 1.0.1 TestFlight version on your device. But if you are trying to send a new TestFlight request it will be sent the latest TestFlight version which is 1.0.2.