Can ILOG BRE integrate with WebSphere Process Server and Lombardi BPM?
Absolutely!
ILOG BRMS, and its successor, WebSphere Operational Decision Manager (WODM), generate "decision services" as web services that you can easily invoke from either WebSphere Process Server (WPS), WebSphere Lombardi Edition (WLE), or IBM BPM.
In fact, to make this even easier in WLE and IBM BPM, you can drag-and-drop "Decision Services" from the Process Designer design palette onto your BPMN flow diagram, and browse the decision services that are registered with your ILOG / WODM servers.