Question I've been wondering, do you pick which companions you want and play the whole game with just those 5?

I like constantly rotating characters in and out as I do different quests, do unless I'm playing something like a MT or a character that can solo use team feats, I almost never get team feats as the character with the other that needs it may not run with me on the next quest.

i chose 5 companions for the whole playthrough and switch one out for companion quest

I switch a few of them out depending on the quest. I pretty much always have Seelah and Daeran (to tank and heal) and then rotate with Nenio (Arcana skill checks), Woljif (Stealth checks), Arueshalae (high damage sniper), Lann (Religion skill checks), and Regill (high damage melee).

Don't use the other ones because they aren't to my liking.

In the case of this game, there are a few characters that I REALLY dislike, and there's only a few that sort of keep the tone I want throughout the game. I'm not a big fan of irreverent humor/brevity in super serious plots, but I realize that not everybody feels the same way.

I made it a priority for everyone to take the Shake it Off teamwork feat. I switch out companions as necessary for individual quests, but I definitely have a preferred lineup (which has evolved over the course of the game).