Why are you talking about hosting a free server for the plugin to use and how much kbps/connections it will need? That will be very difficult to work in my opinion. Just takes 1 bad app to flood and bring the whole thing down. Plugging all the possible leaks and building in restrictions would take the same amount of time as actually building the object.
Why not just make a flexible plugin that you specify the server etc and that's all? Let the developers find their own servers. Running a free server for the community is going to be a real headache and an expense for someone that is probably long term unaffordable.
If there is a demand for a community server, let someone set it up on their own backs, they could even charge a small monthly service fee to its users. This sort of thing will come naturally when it becomes cost effective and there is enough demand for it.
So for now, it's probably best to focus on the object and not the attached services?
so let people with 500 or more posts be the only ones who can use it