1) The two issues are when/what/if web services updates for the next jbossas release (should be, but don't have all the details yet) and which version they will update to. 2.0.0 is GA and 2.2.0 is alpha 4 with beta 1 due in a few weeks (hopefully). I think messaging needs the 2.2.0, so if can get it done in time for jbossws, will probably be that.
2) Only jbossws, ejb3, and unified invokers (which is not default invoker for ejb 2.x in any 4.x release of jbossas) will have problems if dropin remoting 2.x. messaging deploys with scoped remoting jar (which is something like 2.2.0.alpha2)