all f/s and b/s trick names are based on vert skating, or really surfing. it has to do with how you approach the lip, and the way your body faces the edge. for instance, a f/s board-- to do it in a pool, you'd approach it like a f/s 5-0, meaning you come up going f/s, with the front side of your body facing the edge. take it to a rail-- think of the rail as the lip of a ramp, you come at it f/s, because the front side of your body is facing the rail, or the bowl, or whatever you're skating. same goes for backside. because the motion of getting into a f/s board is similar to the motion of a b/s 180 i can see why you'd think it is more related to to b/s tricks, but it's all in the approach. a b/s ollie in a pool or whatever, the back of your body faces the edge, that's why it's backside. making sense?
as for the fakie/nollie thing, it's a little more complex and backwards in it's labeling-- a f/s half cab is "f/s" because of the motion of your body, not the approach of the trick. because the motion is a f/s 180 while going backwards, it's a f/s half cab.
as for the fakie back tail thing, you also have to bear in mind that a lot of trick names came to be before nollie and switch existed. also it's just kind of a skate language no-no to switch between "fakie" and "switch" terminology within the same trick. fakie ollie to switch f/s nose is a perfect example. you start fakie, you should end fakie-- continuous thought and motion. if you start switch, you end switch. therefore, as for the fakie nosegrind tricks-- a fakie ollie to switch b/s 5-0 would be a fakie b/s nosegrind (how your body faces the edge, how you approach).