Sealed Cartridge Square taper bottom bracket, or external bearing? If it is square taper, what length, and did they keep that original or lengthen it? For square taper, I had an FSA Vero and it was cheap and held up fine. If you need a new cartridge BB, usually they are 107 or 110mm spindle length to get chain line right.

I am 6'3" and notice no meaningful difference between 172.5 and 175. I would buy whatever I got the best deal on. Stick to a 50 tooth big ring, as it is close to the 48 original spec and should clear everything. It shouldn't be a MTB FD, but if it is, you might need to replace to work well (curvature of MTB FD usually caps out at 48 and gets hard to set on bigger rings).