So therefore, since I am not Chabad even according to Chabad (lets leave aside the point about following my own minhagim and mesorah) I should eat Shalosh Seudos?
You're asking if a Lubavitcher would say that you should follow Lubavitcher minhagim if you're not Lubavitch?
I mean, I don't see any Chabad campaigns to get people to avoid sleeping in their sukkah, to put Rabbeinu Tams on people in the street, or to stop singing Chad Gadya. You should follow whatever your Rov tells you to do.