As
Nos said, Leaders of the Pack is further clarified and explained in the
SW FAQ (p4):
http://www.games-workshop.com/MEDIA_CustomProductCatalog/m1620228a_Space_Wolves_Version_1_1.pdf
I HIGHLY recommend bookmarking the
FAQ/Errata pages on the
GW website. And reading the main rulebook one, the ones for whatever armies you play, and whatever armies your common opponents play.
Blood Claws and Grey Hunters are primarily distinguished by equipment and how you paint them. For Wolf Guard, depending on what you want to give them, you might need to pick up some more models/weapon bits, either online or by trading with friends. Wolf Guard can all have special equipment and weapons, and the standard
GH/
BC box doesn't come with ten powerfists, ten combi-weapons, etc.
Not sure about your Excel question. Someone in the Tournament Discussions forum was just talking about a free program called Battle Scribe, or something similar...