Questions about HSP PR Visa and Study Visa, and applying to jobs outside my career

Greetings! I have a degree in English Philology, and plan to do a 4-month university exchange followed by a Master in Japan

My questions are the following:

1. Would the time I spend doing the Masters count as years for my PR if I either just study the Master or work in a Part-time job, or do I need a full time job for the time to be counted. I read of the 10 years of permanent residency 5 can be studying, but since I am planning to reduce the time through the point system to 3 years or 1 year. Would that mean I need to work for a year and a half/6 months in those cases?
2. My other question is about work. While being a teacher or a translator is probably a pretty fine job, especially if I manage to work in a university. I might also want to try my chances with Programming. I did not do a University degree of that field, but I do have a Certificate of Higher Education on it, alongside some working experience in the field (not much to be fair, a bit less than a year)
3. For the permanent residency Visa I need to "live in japan for the 10/3/1 years without significant breaks. How many days or times is considered a significant break? For example, would traveling to my hometown for two months if I try to go for PR in three years be considerd a significant break?

EDIT: thinking about it. Maybe its a good idea to do an IT-related master (I think its possible to do a master unrelated to your degree, correct me if I am wrong) to have good chances to find work in both fields? Or maybe a master that is both related to English language or teaching and programming, I dont know if some japanese university offers something like that.