I don't plan on relying on onboard but I have heard a few tests which if in a pinch could be adequate. I plan them however to be only foley ambience stuff. Plus I'm wondering about how I structure interviews and from footage online the onboard mics do a great job at picking up users voice and a close subject so I want to test that out.

I hear you on the zooms, I recognise I'm being a little naive. I guess my thinking is to craft a doc as you might make a movie more than just hang around hoping to get nice shots which gives time for primes be used. If I struggle i'll bite the bullet and get maybe the 14-42mm. The 12-40 looks great, but a bit bulky and pricey. I was thinking to start with buying just the 25mm, a normal that can so most things with effort but maybe adding a wide and a portrait if necessary, i.e. the 17mm and the 45mm olympus.

Again I planned to craft the doc even to the point I wait for natural lighting to be right (probably not making my life easy) So I was thinking to avoid a variable ND which I find gives a very gloomy daylight look. I might however get one if I'm desperate.

On the tripod, I purposely am going to use the Olympus cause of its incredible stabilisation. I can't see any reason to have a tripod slowing me down. Almost all footage I've seen looks as good as a steady cam and if there were any jolts then post would iron it out.

I would strongly encourage you to consider a zoom over a prime. It is nice to have something longer than 25mm for head and shoulder interviews.

If you want to go the zoom route, I would get the Olympus 12-40, or if you are willing to take a size hit, the Olympus 4/3 12-60 SWD. I find the Olympus lenses with the clutch manual focus (or 4/3 SWD lenses) much more usable for manual focus than other native glass.

If you want to stay on primes and keep a low budget, I would couple the 25mm with the Sigma 60mm 2.8 and maybe the Panasonic 14mm 2.5 (both cheap with good performance). In my experience, primes get rarely used for doc work other than sit-down interviews.

If you are shooting outside in daylight, I would recommend picking up some kind of ND system. In my experience, Tiffen Variable ND's are a good middle point between price and quality. A set of separate ND's will be higher quality, but more work to deal with in the field - I would personally go the variable ND route for one-man work.

You don't mention a tripod/head. Is that something you already have, or are you planning to pick up something new?

Sound-wise, be ready for frustration if you rely heavily on on-board camera mics. Capturing good sound is one of the hardest parts of working by yourself, so don't ignore it while shooting or you will pay for it after the fact.