How, somebody PLEASE tell me HOW, do I get my followers to follow my party leader without immediately casting spells or attacking as soon as an enemy appears?

I have Puppet Mode on for all characters, but it seems they will only follow me if I turn on group AI (third eye in the bottom left). I don't want characters to do anything in combat unless I tell them to, but if group AI is turned off they won't follow even if I issue the Follow Me command. Best I can do is to play in Combat Mode (or strategy mode or whatever it's called) and draw a box around the whole party to move them, which is a pain in the ass. Sometimes when I select a different character by clicking on them, the last character I had selected will turn and run towards them. Either the UI in this game is fucked or I'm an idiot. I'm hoping it's the latter because I've always wanted to play NWN2 and this is just driving me insane. Pls halp

In puppet mode, characters will not act/react at all, that's the point of it. If you want to have them follow you without attacking, you need to check the passive follow (not sure of the actual name) in the AI options -- go through the options (press 'C') for each character thoroughly. Neverwinter Nights 2 is not like DA2 or Mass Effect, it's about micro management of the party.

In explore mode, the best bet are the "attack" "hold" and "follow me" commands in quickchat (press V). Those suboptions with a "*" will be applied to all AI companions, so better put them to the quickbar. When they are in "follow me" mode, they are not going to engage enemy until you issue the "attack" command, then switch back to "follow me" after the combat. Other more detail options have to be set in "behavior" tab I think, like setting them to not use spells.

"Sometimes when I select a different character by clicking on them, the last character I had selected will turn and run towards them."

When you give orders to your group, that doesn't include yourself. So when you switch to control a different character, the one who you were controlling is now free, and never got the orders to follow you without attacking. So give the orders again, so that one gets them.

Follow me: Follow and do not attack enemies (they'll ask you if they should attack when they see an enemy)
Stand your ground: Don't move, don't attack unless someone attacks them directly
Attack nearest: Normal setting