I did do a presentation last month for the Mount Baker Amateur Radio Club. One of the local hams (Budd Churchward, WB7FHC) was interested in the potential use of Wildernets on MP02's for field emergency operation center use. Also several hams drove up from Anacortes and one was quite interested in the Wildernets version of the firmware. He said he already had some MP02's.
I haven't done any work on the firmware in quite sometime but it seems very stable and runs on a 5 MP02's in my home near Bellingham. It supports POTS and VoIP telephony with voicemail, IM via Jabber, Rachel web content, and client web pages that provide dynamically generated phone and IM directories. It also provides builtin "getting started" instructions for installing the client softphone and IM apps for smartphones, tablets, laptops, etc.
I keep meaning to put the source up on Github in case anyone wants to browse the code and/or make enhancements.
Wildernets should generally interoperate with SECN however it might take some config tweaks. For instance, the default AP SSIDs would be different and would need to be aligned. I believe both use the same BSSID but I know that Terry evolved SECN to use an updated mesh link protocol while Wildernets still uses Adhoc (IIRC).
In any case, I'm sure you could flash any given MP02 between both versions without issue.