I haven't used the Lynx Express, but I have 5 LOR controllers, 3 SSR4's (DMX option), a Renard SS24 running DMX, and an RPM DMX16DC. All the DMX controllers work well running through the iDMX, and is seen as just a single 512 channel controller in S2, in the way I set it up.
S3 is strongly rumored to control DMX more directly, eliminating the need for an iDMX. Another DMX dongle is required. I don't know if it will have to be LOR labeled or if an Entec compatible such as RJ's or RPM's will work. I'll have to wait for the official release so I can upgrade and test.