I don't intend to play IPY3 myself, so this post may be out of place, but I can answer your question about history.

Shadowclan and Bloodclan had had a rocky relationship many years ago, but many of the people that were causing drama are gone now. The two clans collaborated and allied on Angel Island a few years ago. It was a success as I recall. I believe an alliance or joint effort would be mutually beneficial. Good luck!