OK, I see your point
So, about #1, well what I said is that there are no abstraction for code-assisting things but you probably (if you interested to of course) could try to make your Erlang extension for Che without this abstraction. It would be interesting exercise for us and BTW it would give us better idea about abstraction for the code-assisting things. So could you please give us some idea about of what you have in your Eclipse plugin in terms of Eclipse library etc dependencies or probably you can share your code or part of it. Just to have an idea how you use Eclipse framework. Maybe we could help with porting it to Che and this knowledge would be helpful for us as well.
As for #3 - I would not say we have clear policy about this. Of course, any implementation of REST service can be used on backend the question for us is deploying other than Java web services in the agent - which is rather conceptual than technical problem. But can think about this as well as soon as have something to start prototyping.
cheers,
Gennady