In the intro of ODST, upon meeting Mickey, Dutch, Romeo and the Rookie, Dare turns to Buck and says "Replacements?". Buck replied with "In a war like this, you're bound to have them" or something to that effect. Then while on the last mission, Buck says something like "Its Reach all over again!". Dare screams "We survived Reach, and we're gonna survive this!". Therefore, Im lead to the conclusion that HALO:Reach will revolve around Buck and Dare with their former squad. However, I never read the book, so I could be horrifically incorrect. Its an interest thought though.