I know this is many years later since last post, but I still hope it helps anyone playing and running into this problem. I spent hours trying different suggestions from the internet community with no success. So, here is what I did to get the "Reunions" quest to start: 1) Completed "Get a Clue" quest (the one right before Reunions). 2) Activated the Reunioons quest from the PipBoy. 3) Tried to talk with Dogmeat to activate the quest, but he still didn't do anyting. 4) Exited Diamond City. 5) For some reason Dogmeat didn't follow me, even after a few tries. So, I had to summon him to the front entrance to Diamond City ( 1) Open up the Console by typing Tilde (~) 2) Type 'prid 0001d162', then press Return/Enter. 3) Type ' moveto player', Press Return/Enter. 4) Hit Tilde (~) again to close the console. Dogmeat should now be right next to you). 6) Once I summoned Dogmeat he took off on the quest line...... Good luck. Again, I hope this helps anyone/everyone trying to get this quest line started/working.
