Yes, the in-camera Picture Style has absolutely no connection with MLV.
Pictures Styles are referenced in the metadata of raw stills and baked into H.264 but completely omitted for raw video so it doesn't matter what you use. For me personally, I tend to use Canon's Video-X Picture Style (with the contrast dialed down to 2) just for a visual reference - why? no particular reason.
I don't have a 'golden rule' for exposure and I tend to assess every scene differently using the raw exposure aids - not my eyes. Exposure techniques used in photography apply equally to raw video and lighting is always the most important factor.
It's far more important to make proper use of the raw exposure aids when recording MLV. I always have raw zebras and ETTR hint enabled.
ETTR is great for better signal to noise ratio but it's not ideal for everything.
If it's a difficult, low ambient light scene but has areas of intense point lighting (for instance, a car's headlights), ETTR will mean you are effectively exposing for the car's headlights (as that is the brightest thing in the scene and the thing that raw metering will reference) - thus pushing the important elements into noisy under-exposure.
You will often need to clip more of the highlight information (specular highlights and things that emit light such as headlights, neon signs etc) than you think to get good exposure of the main subject (actor, product etc). How much you need to clip depends on the camera, lens and subject lighting.
I make adjustments to ISO depending on the lighting conditions (lower ISO for well lit scenes and higher ISO for low light) and set the aperture depending on the depth of field (DOF) I want to achieve (but not always possible). The DOF is always dictated by the lens aperture, the maximum useable ISO of my camera and, most importantly, the lighting conditions. I then frame and focus the shot before hitting record
but..
If I'm shooting MLV on my old 50D, I know that the maximum useable ISO is 800 before noise becomes too much of an issue. If I use my widest lens (F1.4 50mm) I know it is too soft at maximum aperture so the widest I can go is F2.0. If I do not have control over scene lighting, these 2 things limit what I can hope to achieve with that camera and lens combination. If I can't get a good exposure within these limits I simply don't hit record.
When it comes to dynamic range you also have to remember this:
The lower the ambient/available light is = the wider the lens aperture needs to be + the higher the ISO you must use.
As you increase the ISO you decrease the maximum dynamic range of the light being captured/recorded and as you open the aperture wider it will also decrease the DOF. What this means is that sometimes you just cannot hope to get the shot in the way you envisaged, or even not at all. The available lighting and your equipment (or lack of) will limit what you can hope to achieve. It's technology and physics.
Canon DSLRs, in optimum lighting conditions can capture ~11 F-stops (scene linear) but this only applies to optimal lighting conditions. In reality it's more like 8-10 F-stops at best. A wide, establishing shot of a night time city scene, with a mix of very dark areas (alleyways, unlit shop interiors etc) and very bright areas (street lights, illuminated shop windows and car headlights) can exceed 15-20 F-stops so you, as the DOP, must choose what it is that is most important for the audience to see and expose for that.
