Yes send gga out the S1 port at the data rate specified in the Panda .ino directly to rx/tx to the teensy uart for gps1. Emlid ttl is 3v, but power supply is 5v.
Or optionally use a ttl to ethernet adapter on the S1 port like the EPort 20, and use my Panda .ino and setup file for the eport. But change the baud to 115200.