Suicides prevail at both ends of the spectrum of social interaction: too much or too little [1]. It's not just at the too little end. Examples of too much social interaction leading to suicides: prison suicides, overworked stressed out students, suicides due to too much debt or career failure, individuals, usually women, left alone to take care of too many children alone without support, and altruistic suicides such as when elderly go into the wilderness to free up resources, or soldiers jumping on grenades. It's not just loneliness that kills. You have to plan ahead and manage your interaction such that you don't leave yourself without anyone, and have a support network and realistic expectations in life.
All of your examples could include "too much social interaction" as their primary cause, but seem unlikely to, to me. Just because a suicide isn't caused by lack of social interaction, doesn't mean it automatically was caused by the opposite.
Basically, either you kill yourself, because you see yourself as unfig with society, either because you are too fit for society, at a point you are ready to die for it. The kamikazes are a good example of that.
The "too much social interaction" suicides you describe are really not about social interaction, but rather a lack of resources (mental, financial, etc) to adequately cope with various social demands. I don't see how it's really social interaction at all, in the colloquial sense.
In my examples the lack of resources in themselves are not an issue, it's the lack of these in the face of social pressure/involvement (kids, parents, coworkers, etc).
[1] http://en.wikipedia.org/wiki/Suicide_(book)#Types_of_suicide