I think you need more voices - it's too obvious that your doing both, and there's just no possibility of humour when 1 guy is having a conversation with himself, sorry.
I would suggest starting out solo - like 1 guy, your voice, no accent, out there in the Arma2 wilds - when you find someone to play another character then it will make sense, there will be actual conversation and interaction that will be a lot more natural.
If you have to voice act, then heck the only advice I would give, is to throw the words out there... you have to kinda project your voice right through the mic or it sounds like your reading from a page. Know what you have to say then say it your own way. Only record vocals when you have the house to yourself, no background chatter or embarassing explanations - if you don't feel comfortable then that will ruin any recordings that you make.
I think that when you have someone doing the project with you, then you'd be able to bounce ideas off each other, develop persona's properly, and have a lot more fun doing it. A lot of people want to get into this stuff, live streaming, machinima etc, I'm sure you'd find people to play other roles. The trick I think would be to get to the point where people want to join you.
Maybe I'm over-thinking it, but I think your over-thinking it

... Why not just be yourself? Battlefield Friends works because we can believe that they are mostly real people - the characters are defined and have personalities, the only way to achieve that is to have your real personality leak into your character.
Personally, if I was going to do something like this, I'd start up my own server and just mess with people who join - like some mad hermit, making obscure server rules and being precious about every vehicle. Something fertile like that where plots will just evolve and content won't have to be planned so much as it'll just happen. I'd consider not doing Arma2 as well... maybe keep an eye on that new free-to-play SOE zombie survival game, might be better for viewers to go for something brand new like that instead.

I am the one who knocks...
