One more observationn is that the mdb node console log shows the host name as JmsNode1-org-int and JmsNode2-org-int, Should it not be JmsNode1.org.int and JmsNode2.org.int as I've specified in the standalone-full-xa.xml? From where does it pick the value for host in the intialCconnectors spec using the hyphens I'm not sure..
[initialConnectors=[org-hornetq-core-remoting-impl-netty-NettyConnectorFactory?port=5445&host=JmsNode1-org-int, org-hornetq-core-remoting-impl-netty-NettyConnectorFactory?port=5445&host=JmsNode2-org-int],
.