I don't mean to rain on your parade. But nothing you've written above actually matters.
The tech for a social network is a solved problem
The HARD unsolved problem is how to keep the social network running and monitized without going down the VC Funded death spiral.
You are literally making this post on a social network (hackernews) that is as old as reddit. They both roughly do the same thing.
Yet reddit is self desctructing. But hackernews is still running just fine, and still has a great community and high quality content and comments.
Have you stopped and asked yourself why this is so?
The first is a VC funded company that is expected to generate 100x return or die trying
The latter is subsidized by YCombinator to generate a funnel for their accelerator.
If you can't answer the question of how your social network is gonna stick around like hackerenws, and not self destruct like reddit in 10 years, then your social network is irrelevant in the grand scheme of things.