In 2017 I went on three-week long Three Passes trek in Nepal, with porters -- I carried only my day pack. I took only X-T2 with 18-55 kit lens, and a very lightweight travel tripod.
This turned out to be completely sufficient, and I was glad that I didn't carry more gear. The altitude is physically demanding, so you want to go as light as possible. I do have mountaineering experience and packed accordingly.
Most of my pictures were of people, villages, plants and miscellaneous close-ups. For landscape shots I was content with the reach of 55mm. Tripod was for long exposures and selfies.
Other tips:
I also had an iPhone, Garmin inReach, three camera batteries, adapter for their AC outlets, power bank, chargers for all devices, camera & lens cleaning supplies, spare SD cards, and a waterproof bag for all devices in case of rain.
I had the camera in a holster bag (Lowepro Toploader Zoom 45 AW II) strapped on my chest to the backpack shoulder straps with quick release buckles. That allowed quick access to the camera, with neck strap around my neck when shooting, didn't bounce around, and protected the camera from dust, which is often abundant and blown by wind on frequented trails. I would not carry the camera unprotected for prolonged time, like, e.g., on Peak Design Capture clip.
Become familiar and proficient with your camera. Figure out proper aperture for desired depth of field -- I didn't, and missed some focus. Same for hand-held shutter speeds -- with physical exertion and heavy breathing your hands will be shaking. At least halve the recommended SS for the focal length. An app like PhotoPills will be useful.
For me, the main enjoyment of the trip was hiking, seeing and experiencing the nature and local culture. Photography was enjoyable, but not the main focus or objective of the trip. I think trying to turn the trek into a photography hunt takes away from the enjoyment. There are so many things and scenes to photograph, don't try to capture it all -- rather look, see, take it in, revel in the experience with your family.
With today's lens choices, I'd go with XF 16-50 or XF 16-55/2.8 II. I also have XF 10-24 and XF 55-200 that I use on shorter hikes, but would not drag them on a Nepal trek.