I’ve done the trek, and it definitely isn’t a place you see much wildlife (including at lower elevations). I assume you are starting in Lukla? If you are starting lower than that, maybe there are more birds, but I just don’t remember seeing much from Lukla going up. The only other “wildlife” are dogs and yaks.
Are you going with a dedicated photography group? A dedicated trekking tour? Or independently? If it is with a dedicated trekking group, you may not have as much freedom to linger to take pictures as you might hope. The goal of each day is to get from point A to point B (or to acclimatize on rest days) on that style of trip. This does open up beginning and end of the day opportunities before you start and stop when there can be good light. There are certainly plenty of options to make pictures, but you kind of just have to grab what opportunities there are and be accepting that the focus of the group isn’t you taking pictures. Obviously, if you are with a bunch of photographers on a workshop or if you are doing it independently, you have a lot more flexibility.
The other thing - after you get to Tengboche, almost everyone starts to feel the altitude no matter how fit you are. I went with grand hopes of doing some dawn, dusk, and night photography……and basically did none because eating a warm meal, having some tea, and getting into a warm sleeping bag quickly became the routine at the end of each day (and the priority).
If I were to go today, I’d probably take a Z6ii and the 24-200 or a z7ii and the 24-120 and make the best pictures I can with that. Maybe I’d take a 35 or 50 for pictures of people and for Kathmandu. I definitely wouldn’t schlep a tripod. I would aim for as little weight as possible in your daypack (and don’t expect to have access to the bag the porter is carrying outside of at the tea houses, as they walk at quite a different pace than you will be walking). You will be drinking more than usual - I purified about 5L of water a day which was all in my daypack each morning. The temperature can vary wildly as well, so you will likely have multiple layers, hats, gloves, etc in your day pack. You can easily have 15-20lbs on your back and a fairly full pack before you put in any camera equipment.