I have tended to use the 16mm a lot for landscapes. This is probably my favourite at the moment. I really like the mechanics, aperture ring, clutch focus (using the flim setting for manual focus) and the exxcellent image quality. It complements the design ethos of the X-T2 very well. Over the last 2 years the mainstay of my images with the Fuji has been the 10-24 which is a great lens.
The F2 WR primes are a great solution for lightweight (23/35/50), personally I wouldn't go down the 18 route, though it is lightweight, I don't think that it's 'sharpness' will meet your standards!!!! I would add 16mm to that set, as it's a great quality lens, F1.4 and has WR, then if the inclination desires add the 90mm
Thanks chaps - I've always wanted to try the 16/1.4 and the 10-24 zoom. I previously had the 14/2.8 which was superb (and small).
Mr P. I previously had the 18/2 and must say I rather liked it. As you say, it's very small, but I also found it fast to focus and reasonably sharp (when suitably stepped down). Here's an image I made back in 2016 using the 18/2 with my old Fuji X-T1 at f5.6 (in retrospect, it would have been nice to step down to f8, but the sharpness at 5.6 is still pretty good) The purple cast is due to the fact I was using a cheaper 10 stop ND. (I rather liked it at the time as I thought it had a Velvia like quality) I might have to go and re-take this image with my Firecrest 10 stop ND and the D800E / 24-70....
The downside of the 18/2 is that it doesn't have WR.
Caldecotte Lake by Amar Sood, on Flickr
Fuji X-T1 / XF18mm f2
Lefty