... from the Nikon F days in the 50-60s. F mount, non AI. Then in the 70s the mount does not make use of the rabbit ear but a notch in the aperture ring and is called AI. Around the 80s we have the AIS, which is an additional knob on the aperture ring to tell the camera more information...
Your dates a bit out. Non-Ai was up to around 1977, and Ai came with introduction of Nikkormat FT3, Nikon EL2, F2A and F2AS, followed shortly by FM, FE and F3.
And just a historical note for those nostalgic persons where old is good, for non-Ai you need to set your aperture to f/5.6 then release your lens. The lens to be mounted must also be set to f/5.6 so that the rabbit ear catches the latch.
That's not all - you then have to do the click click - twist the aperture to minimum then back to maximum to "index" the lens - to tell the camera what's the maximum aperture of the lens you've mounted.
That's why the new version is called Ai - for auto indexing.
Minolta, Canon, Olympus, etc all had "auto indexing" from the 1960's, Nikon was just plain old slow in getting the Ai bit going.
There is no additional "knob" on AiS lens, there is a groove at the rear lens mount.
AiS came around the time the E lenses were released, quietly. First 2 cameras to use AiS were FA and FG. AiS came with uniform aperture movement controlled from the mechanical lever at the lens mount to allow shutter priority and programmed exposure. For all intent and purposes today other than FA, FG, F-301, Ai and AiS lenses are functionally identical.
Again the S and P mode had existed long before Nikon did it. Just plain old slow.
... I think some of the plastic G lenses are made by Tamron ...
That's plain old speculation, although the same was speculated by many people.
S5 Pro allows the use of old AIS and AFD lenses. Fuji will surely appreciate these older Nikkors as much as the new zooms.
S5Pro is simply a D200 with a Fuji sensor. Fuji simply took the body from which they want to carve the camera out, so the ability to use manual Nikkors is really Nikon's decision, rather than Fuji appreciating Nikkors.
Anyway, Fuji makes fantastic lenses. It will be great to see Fujinon on Nikon F mount. But thats a far fetch dream.
That's also a not very accurate information. Fujinon lenses made for 35mm film use were good lenses, but never fantastic lenses. The legendary Fujinon lenses, IIRC are for broadcast equipment, not for 35mm.
Hope this helps. Just for your information, I own a Nikon F Photomic FTn, Nikkormat FT2, Nikon EL2, FE2, FG, F70, D70, D300 and D60. I also have several S2Pro. I have pre-Ai 50/1.4, 105/2.5, 28/3.5, 24/2.8 (the last 2 converted to Ai), Ai 50/2, 28/2.8, AiS 105/2.5, AF 35/2, 85/1.8, AFD 50/1.8, AFS 60/2.8, plus a few AFD/AFS zooms. I at one time had to click click to index the lens for a wedding shot, before the coming of Ai Nikons.
In the good old days it was really troublesome to use Nikon...