To answer your questions:
1. I am using MZ
2. The CSV file is huge with over 1730 lines, I can take multiple screenshots of it. The only one that is not being translates is the Text (s) atm.
Line 444 is the Text (S): it is not being translated, the next line (445) is a normal Text line and it is being properly translated as the rest of the file. Only the Text (S) is not.
3. As for the plugins I have tried turning them all off except for yours and I get the same result.
I removed the VisuMZ_1_OptionCore to allow the normal options to appear and be able to choose between languages and it works.