Nice addon! The only problem I've run into is whenever I separate the SLS Core stage with the Orion MPCV attached orbiter CTDs. When I check the logs there seems to be nothing wrong, no missing meshes or textures. I've disabled things like StateSaver and other things that don't agree with Velcro, but I have had no luck. When I use the CEV Orion instead of the Orion MPCV there are no problems with staging.
EDIT:
I was able to find the problem. The Orion MPCV scenario and the MPCV Moon scenario seems to have something wrong with the fairings (perhaps an invalid name or reference) that was causing the scenario to crash at startup. I tried using the Orion MPCV's default fairings with the FAIRINGS line in the scenario. That seemed to work, but when the ICPS would separate from the core stage it would crash. I then used the fairings from the CEV Orion scenario and everything is working perfectly now.