arduino_student_17:
Is it still an issue to connect the HC05 to Rx0 and Tx0 when I've got the Mega not connected to the computer?
That will work fine. But during program development it may be better to keep Rx0 and Tx0 free.
Is it as simple as and if statement about Serial1 or Serial2 and then reading in that data?
I don't understand what you are asking.
The way I would do it is have a function (copied from my tutorial) called (say) recvSerial1WithEndMarker() for the Serial1 input and another called recvSerial2WithEndMarker() for the Serial2 input etc
...R