Yes, that's what I was thinking as well for your latter suggestion.My apologies, I don't know all the differences between trim levels. With the opener switch being right there, it shouldn't be too hard to install an additional switch. The important question would be where to mount it and how to protect it from accidental activation.
Just thinking out loud, if I were to do this, I think I'd mount a momentary switch in the cubby where the jack is located (easily accessed and protected from accidental activation). Another location might be in the area where the manual unlock panel is, remove the trim panel, hard mount a momentary switch that could be reached through the open access panel and with panel cover in place, it would be protected from accidental activation.
There's a removable piece of plastic trim on the inside of the tailgate as an emergency in case someone got locked in.
I removed that trim piece already. However, I'm trying to come up with some manual switch that makes it easy to open from the inside.
When I find a way to do this I'll post the results