Advice on setup for short documentary ?

Hi everyone !

(First, i just want to clarify that i'm a student, i've never done professional work and have very little experience on set. I'm still learning.)

I'm shooting a short documentary (which is a part of a short fiction film with a decent budget, but the documentary part has to be very very low budget), in just one day. It's going to be a discussion about art between a group of people, around a table, in the evening. We really want to let the people talk and shoot by improvising. Kinda Guerilla Filmmaking style.

So i found a guy renting a set, and I thought it could fit well the vibe : Sony FX3 + GM 20-70 + RS 3 Pro. The zoom would give me a lot of flexibility since it's a documentary. But I've never worked with this lens. Also, don't know if it does well in low-light, since it's taking place in the evening/night.

Or, I was thinking of DZO Vespid Prime, since I like their look, but don't know if it's going to be convenient since it's a prime lens.

Also, I'm thinking of taking another operator for a 2nd camera, with maybe a prime lens, to get a different view. I don't know if it's worth it.

And finally, i'm wondering if I should get a follow focus, or go with AF. It would mean even more money, since I would go for Nucleus M + Teradek + Small HD. Don't know if it's worth it or if i should rely on autofocus !

So yea i would like advice on the lens and the setup, if you've ever tried it, or if you recommend something else ! Thanks :)