1) It depends. With a 16 MP sensor, the D4 isn't going to be outresolving some of the D-series lenses, except in the corners. An advantage there is you can use more modern lens designs on film. Also consider that manually focusing on a DSLR isn't really worth the effort and the likelihood of missing focus.
At the same time, the D series lenses universally handle like plasticy shit with respect to focus and aperture rings, compared to AIS lenses. The experience is decidedly subpar. The F4 autofocuses with G lenses fine though. You could shoot modern lenses on film there, and if you want to use the FEs, then you have the 24/2 AIS anyways. Considering that, you could go for all G lenses.
My thinking is this:
Zoom lenses age poorly; you should get the newest one that you can afford.
Prime lenses age better; you can stand to use older designs here. A 105/2 is still a sharp lens by any account, but it won't test as good as the 105/1.4E.
Now there are points to make here, with respect to wide angle landscapes.
a) Tilt-shift lenses. If that's your thing, maybe look into the AI-era ones.
b) Compared to the AIS versions, the 28D and 35D are inferior. The 20D is the same lens I believe. The 24D's a different design, but ok by all rights. The Gs, naturally, are vastly better in flare control and corner performance, particularly with the wide angles. That might be the deciding factor there.
c) The 14mm is ancient and not that great. Get the 14-24 if you're going that way. The 17-35/2.8D is alright, and is backwards compatible.
2) The one with features you want
3) Mamiya 7