Oops: Documentary shoot with little experience, and little gear. Any tips?

I'm on a work trip with my boss in a remote location, and have been requested last-minute to capture some footage of the activities, and a talking head interview, as I bought along my A7C R for personal photography.

Really wasn't expecting this and there's no other option (we're in a remote area and it's tomorrow). Thankfully, I have a shotgun microphone and a tripod, but other than that, I have very little experience. I would really appreciate any tips or recommendations for making the most out of my situation. I've explained my limitations, but something is better than nothing.

1. For the interview, should I angle perfectly eye-level, or angle it slightly down?

2. For the docu shots, stable handheld shots will be a challenge. I'm thinking active steadyshot + frame wider + high shutter speed + stablise in post with Catalyst Browse. Does this sound like a good option?

3. Worried about the sound -- I have no wired headphones, so cannot monitor. Any tips? Can I position a phone as a backup mic (in their pocket?)

4. Any other tips for my predicament? I'm more of a photographer, not a videographer.