These days I use Fujifilm only for personal work and I use the X-Pro2 because I like that camera best. So for me the 35/2 is the better option as it blocks less of the optical view finder. Moreover, I personally love the small form factor of the 35/2 and I don't shoot portraits with it that require shallow DOF and very smooth bokeh. I use it mostly for (urban) landscape, so the better sharpness is well-suited.
I would only opt for the 35/1.4 if I really needed the extra stop of light and/or would do specifically portraits with the lens.
PS. I also use it for street photography (X-Pro2 + 35/2) and because of its much faster and more accurate AF, I tend to loose fewer candid shots with the f2 compared to the f1.4 version.
Hi, I've owned all of these lenses (and quite a few more Fujinons) so here's my personal take on this.
The 35/2 is a fantastic lens when it comes to image quality. The 16-55 will not reach that level. It's closer to the 23/2 and the 18-55. In fact, the German magazine Fototest has tested the 16-55 and the 18-55 and both are very close to each other in terms of sharpness. The 16-55 is a bit less sharp on the wide-angle side and the 18-55 is a bit softer on the tele end.
The main advantage of the 16-55 over the 18-55 is better contrast due to better coatings. The images look a bit 'punchy-er'. You could get a similar result with the 18-55 in post by cranking up contrast, but the 16-55 has a better 'starting position' here. The 23/2 is a nice lens. The main advantage is size/weight, speed of AF and versatility of the 35mm equiv. IQ is good but nothing exceptional like the 35/2. With the 23/2 it's best to avoid f2 when you want good IQ, so effectively it becomes a f2.8 or f4 lens, just like the 18-55. So, it's easier to leave your 18-55 on camera and zoom to 23mm, instead of mounting the 23/2.
The 16-55 is quite a bit larger and heavier than the 18-55. For travel and carry-around I would prefer the 18-55 as it is also image stabilized (the 16-55 is not). That allows you to shoot in available light situations like indoors. Esp. since the X-T3 doesn't have IBIS. The 16-55 is meant for more professional shooting conditions, with controlled light, shallower DOF, WR and front lens coating that repels water. I've used it for several assignments during when I was using Fuji for professional work. It's a work-horse lens, just like all 24-70/2.8 lenses from major manufacturers. The downside is that it is almost equally large and heavy, despite it's only for APS-C format.
When you look for a great travel kit, you might consider to sell your 23/2 and buy a 14/2.8 next to the 18-55. Those two lenses are made for each other. Same filter size, lens hood, very portable and great IQ for relative low costs. You can always keep the 35/2 whenever you need more than f3.8 (which is approx. the aperture when you zoom the 18-55 to about 35mm). That way, you probably use the 18-55 more than 90% of the time. The rest would be the 14/2.8 or the 35/2. This however, depends on whether you need something wider than the 18-55.
