Hello!
The overall complexity of this task depends on how good do you know the application and the RabbitMQ internals.
I don't see any problem in recording RabbitMQ-based client-server calls, but the built-in VuGen environment filtes would'n help a lot, because at a glance, RabbitMQ implements its own set of classes and interfaces for most of the work,
so including WCF filter is not a solution.
You will want to create a new custom recording filter, add the RabbitMQ.ServiceModel and RabbitMQ.Client DLLs to this filter, and include the corresponding interfaces in the filter. You will need to make some investigation on what to include, I couldn't help here because this framework is new for me.
Next, regarding single instance restriction. As soon as you are already using cloud in your solution, I can suggest you to try LG Cloud via MS Azure, it could do.
If the restriction is related to some internal thick client stuff, that would not affect the replay, then running several instances alongside should not cause any issues (because we suppose we extracted only pure RabbitMQ client-server interaction script), but only the way of trial and error would fork here, as for me.
Kind regards, Alexey Bondarenko
LR RnD, .Net protocol