No i think that those 3 will not be in Hobbit. Beacuse LOTR adventure is many many years later when Bilbo is already old. In Hobbit, Bilbo is young that means those 3 werent even born yet. Well...Merry and Pippin they did not born yet. I forgot who Haldir is. So i think they will not be in Hobbit.
The Hobbit happens about twenty years before Merry and Pippin are born. As for Haldir, I wouldn't think so, as they don't travel through Lothlorien, but there are opportunities for him to make an appearance. Apparently Galadriel is in Rivendell at this point, so he might accompany her as a guard, 또는 he might appear in the battle of the five armies (though I highly doubt that - Thranduil doesn't get on with Rivendell 또는 Lothlorien so he wouldn't want to fight with them.
