1) I read this fic a long time ago - way back when I first started to read in this fandom.
Jim was a unicorn shapeshifter and Blair was some type of wizard. I remenber it was a WIP and the author also wrote other fantasy au's.
2) Blair sends his young son home to Cascade for Jim to take care of, while he tries to get home. I think the boy was also called Blair and that he looked very much like his father. He was also really good at football because he played with the other children in the village that the grew up in.
Thanks for the help.
ETA: Found by the brilliant and sparkling
stasha2g