A great article, although I would add that all of the strategies that you mention require a lot of discipline to use correctly. (although meditation in even small doses does help with disengaging the sense of self).
I would not consider flow a technique to disengage the self, but rather a symptom of when the sense of self is disengaged.
There are also techniques that make use of removing emotional Armour (such as reichian therapy), which also lead to a decreased sense of self.