Yup, Constantin is right this will take some coordination. Try to get involved on a prep day so that you can setup and test the workflow in advance. You should also be paid for this day, the camera dept will be.
Couple things from my experience with Reds and G3s to watch out for....
There is a good chance that the red, once fully setup with all the accessories they plan on using, will emit a huge amount of RFI/EMI interference that will swamp your little G3 receiver. To see this in action keep your transmitter off and tune the g3 to an open frequency. Now bring the g3 over to the red (powered up with all accessories running) and watch the RF meter fill up. I’ve found there’s just not much you can do about this. Placement can help a bit so experiment with that and sometimes a bad BNC cable or power cable is to blame. But I’ve found it’s almost impossible to get ACs to start swapping cables out that are working perfectly fine for them.
Ultimately, it will probably work work fine because once you power up your transmitter it should still lock on as long as you don’t push it with the range. You just need to be aware of the limitations. A more robust receiver like a 411a would be better. SRs have also suffered with Reds in my experience.
Red audio settings are irritating at best if you’re not familiar so give yourself plenty of time to fiddle with that. Depending on the model and input accessories available you may need to pad the receiver output down to mic level in the g3 menu. I usually have the camera guys put the “A-box” on and that allows me to use the standard XLR output cable for the g3 but you could go a few different routes.
The biggest thing is to just make sure you have enough time to do all this and test and not try to squeeze it in just before they want to roll.
For the playback back part I’d recommend finding a small powered speaker (Speakeasy or Foster) that you can connect to the monitor to boost the volume. An sdi connection from camera to monitor should carry your audio along with it as should a teradek transmitter unless it was setup to omit audio. Careful with feedback and make sure it’s off when not working. Unfortunately it’ll probably be up to you to babysit it.
Lots of places and device menus to get bogged down on this one! Good luck.