These are rather broad questions. For example, I'm not sure if you need filters. What are you shooting? What's the nature of the documentary? Who is shooting it - are you hiring a professional DP or are you doing it yourself? Will there be a sound person, other crew? Why do you need a second camera? What are you using that for? etc etc.
I would add at least China Ball light fixture capable of using a 100 -150 watt bulb and a Router Speed controller from Harbor Freight for a dimmer.
For audio, mixer, (sound devices 302), Sony MDR 7506 headphones, a hardwired lav, a wireless lav, a boom, a suspension mount, some sort of fixture that allows the boom to be locked down on a c or light stand.
If you want to shoot outside, you'll need wind protection for the mic.