I'm curious, since I think the XR5 is just as unrealistic as the XR2, what you might have done to the XR5 to make it more realistic. I'm not getting critical on your choices though, where someone puts the realism bar is their choice, and this thread really isn't about that anyway.
About inclinations, are you launching the Soyuz out of Baikonaur? You might just set the inclination to ~51 degrees, though you might have more 'latitude"
P) by giving Kourou's Soyuz site a fictional upgrade for manned launches. Given the vehicles you propose using, Soyuz might be the one you'll have to tailor inclination around, but that's just an first guess based on what I know. Jarvis family rockets should be capable of whatever you care to throw at them for station building, so I don't expect them to be a constraint. I don't know diddly about using the Themis-A or the HCLV, so I can't add anything there. Depending what you do to the XR5 that may have it's own constraints.
Also, what is the purpose of the station? Human studies, manned earth observation, materials science, or what? People in a can for fun and science doesn't actually require those people seeing much of the planet(lower inclinations), but earth observation does. It depends on what the stations goal is, and since I don't know what you got built I can't say much now, but I can if you post more.
TL;DR: ~51 degrees, to accommodate the Soyuz.
Also, while I'm interested enough to talk and help out with planning, I'm quite sure I won't have time to fly any missions, so my opinion shouldn't go over a person who is interested and willing to fly. This shouldn't be tailored to my tastes, especially if it isn't fun or reasonable for anyone else. Just saying.