Hi Alexx,
RabbitMQ is extremely efficient in managing connections. It can handle several thousands of connections concurrently if configured properly. I would not worry too much about that.
What is the reason you are co-hosting all those endpoints together in a single process? Because it seems a bit of an antithesis to your initial split. Although your documents are separate and split out they are still tight together in the same host. Thus if you need to change a process for a single document type you have to take all the endpoints down. If they are truly separate and unique why not have single deployable endpoints and hosts?
Regards
Daniel