Seeing your answers and desire to be able to do much in post easily, I think there is no camera in the 1k price range that fits your need. If you stay in that price range you will need to compromise a lot on everything. I would advise you to save more and get a higher end camera like an fs5 with an external recorder, a blackmagic ursa mini or wait for the panasonic gh5.
First : copyright it. Then there are really a lot of different direction for the next steps and it depends on a lot of factor, on you and what you want to do. Do you just want to sell it, do you want to direct it, will it be an expensive film, a short, a feature, who is it aim at, etc, etc.
My advice, don't buy this guy's camera in second hand.
I have both the zoom and the rode vmp and I can tell you for sure to put the +20db preamp from the rode vmp, it is way better than the zoom preamp, just be carefull in noisy places as you can saturate easier. It's a great setup you will have very good sound with it.
Here is a film where they did something similar, it's a one shot, point of view film but with hidden cut : https://vimeo.com/90068717
And here is the behind the scene where you see how they cut, they used aftereffect in wich they did mask and tracked the mask to cut from one shot to the other : vimeo.com/100157873
Good point from Eric. In terms of ease of use and image quality my choice is the A7sII but it's true that sometimes size matter for the client. That said it also matter on your shoulder, a bigger camera is heavier and if your client are fine seing you with a dslr they will be fine seing you with an A7sII.