>>4686
>then learn at least another one
If so, I would recommend a language that doesn't require learning a new alphabet. This is my experience, but Japanese from scratch is very difficult, because it has both a new writing system as well as the vocal part. If you can already speak a language as a native, you only add the writing system, and vice versa if you already know the writing system because it's the same as a previous language. Unless you are very gifted, I just think it would be very demanding to learn a completely new language "on the side", it takes more effort than that.

>I live nearby (thus making me taking on shifts, even if erratic, that much easier
This is probably a good idea. Tell them that you are a student and "need some extra cash" and they won't feel they have to take responsibility for you if there is not enough hours. Idk about your place, but where unions are strong, it can be an issue to work only a little because companies may expect that you want more hours and then they won't hire you unless you have a different main occupation.

>typically takes four years
>University of the People is also a fully online university
Studying only online can be a challenge, and for 4 years it may be even more difficult. Again I don't your expectations or the local culture, but I suppose this means you have little contact with other students, meaning less chance to exchange experiences and learn together with others. Doing this for 4 years can be hard if your only means of communication is an online forum at most. With group projects only online, there is a risk some people become impossible to reach for unclear reasons, or they drop out. This is something to keep in mind for distance study.