I created another project to evaluate the the feasibility of the solution:
https://github.com/fax4ever/ogm-wildfly-play/tree/master/ogm-remote-task

In my opinion the solution the solution is feasible, because:

(1) Compatibility mode could be enabled without any trouble for Hibernate OGM cache
(2) The big marshalling issue, server side is the same of client side, already solved by Sanne in the actual Infinispan Remote dialect
(3) Operation objects are not serializable, but we can create similar, serializable objects, to be passed to the remote task.
(4) Embeddable objects are currently created on separate caches, so the maximum possible level of nesting on all caches is 1, so tuples and association tuples could be passed to server as Map<String,Serializable>.

My opinion is that: the problem is just time, the change requires a good effort.