Woah, nice! looking forward to it.
The only thing I miss from vanilla Skyrim however is the crossbow (which I think fits amazingly on Enderal's slightly more advanced technology level). Is it possible to "trim" the Dawnguard esp to make it "compatible"(as in, just include gameplay stuff, not the worlspaces) with Enderal? possibly including on the launcher, checking if the user legitimately owns the DLC? I really wanted to use the crossbow on my second playthrough