Pyp and Grenn are still alive in ADWD, but Jon becomes distant with his old friends. Characters who died in the battle in the books were not on the show, and for the most iconic death, a character's named Donal, they substituted Grenn.
These two characters faded completely to the background once Jon becomes Lord Commander (and the issues Jon now faces as Commander are of a different nature), so it was a good opportunity to weed out the recurrent NW cast a bit, and get a pay off for s.1 to 3 by giving these two a "good exit" instead of having actors confined to the roles of extras from now on. They might or not replace them with other NW parts required for what comes next (eg: the commanders of Eastwatch and Shadow Tower). The rescued boy Olli who killed Ygritte, seems to replace a male whore from the books, and thus will likely stay on to become Jon's steward (Satin's next role in the books).
From now on Jon will be kind of isolated and mostly face antagonism rather than friendship, except from Sam who will get him elected first (and he will be able to discredit the leading choice Janos Slynt as a coward on the show.. oh the irony). Soon after his election, Jon sends Sam to the Citadel with Maester Aemon, Gilly and Mance's son saved from Melisandre.