Darks are not only for removing amp glow but also help to identify hot pixels and help reduce sensor banding in the background noise. So it still is advisable to use those. Bias you only need if you want to scale a master dark from one exposure time to another. If you always plan to shoot at the same exposure time then you can do without bias. Or you can consider shooting a series of masters at, say, 30, 46, 60, 90, 120 and 300 sec and create masters for them.
Note that you'll need darks for the flats (commonly referred to as dark flats or flat darks) as well. You can reuse the darks for the lights but then you'll need bias again. Or, again, shoot a series of dark flats of, say, 1, 2, 5, 10, 15 sec and make sure that your flats always use one of those exposure times.
Regarding gain: the sensor has two modes and switches mode just under a gain of 100. See the manual and the product page of the camera. There it is explained how this works and what the result of this mode switching is. Whether to use a gain of 0 or 100 depends on the local circumstances where you image and if you plan to do narrow band imaging or not.
