Over the course of my entire game I have been trying to phone each of the protagonists in order to get this trophy. Each time I successfully 'Hang Out' with one of the characters the other one is always unreachable (busy tone on their cell) or not interested.
What is the easiest way to get all three characters together in order to get this trophy/achievement?
Secondly, there are obviously points in the story where this is not possible due to certain characters being otherwise occupied. Is there a best or easiest time to get the characters together?
Specifically:(End game spoiler)
I want to know if it is still possible to get this trophy in post game. I choose option C: Deathwish which resulted in all three characters surviving (and becoming friends again) but I still can't get them all together?
Best Answer
How to get three characters together
Before you can do this you must complete the story mission "Friends Reunited" to be able to have all 3 characters hang out together. After that you can call the other two characters via the "Contacts" icon in the in-game mobile phone.
Make sure you call both other characters immediately before picking them up, because if you pick one up first before you call the other then you will get a "busy" tone on your phone.
Being able to get "Three man army" trophy even at final mission or after
"[MISSABLE] This trophy can be missed if you have not unlocked it by the time you get to the final mission. Make sure you choose "Option C" when offered the choice, after which this trophy is no longer missable."
According to the following link and the above text you should still be able to obtain the trophy.
http://www.ps3trophies.org/game/grand-theft-auto-v/trophy/68567-Three-Man-Army-.html
If you didn't get the trophy before the final mission, and choose option A or B, then you're not longer able to do it.