Just to present another perspective. IS research can be broken down into 2 broad categories: economics- or organizational-based. I agree with your strategy to do a Master (transcript/LOR), but I would suggest you to consider a Master in either economics or OB-related areas (e.g. psychology, sociology, etc). Think of economics/psychology/etc. as the backbone or foundation to your IS research question. Take a look at the research papers that interest you, and see if you agree with me.
If you intend to take MSc in IS, I suggest that you take as many econs/OB modules as possible, depending on which track you like to pursue in your PhD IS program.
Btw, I look at the courses for MS at Texas A&M (
Course Sequence | Mays Business School MBA Program - not sure if this is the one that you are referring to.) I would say none of the courses is
directly relevant at the PhD level. Indirectly, they might (e.g. give you some research ideas/questions to pursue).