As far as I know he can't change contract terms without the players' signature. Like, he can't simply increase their buyout prices willingly just because he wants to ''make their lives hard''. Both parts have to come to an agreement for that to happen, it's basically a contract renewal. Fnx's contract with Immortals ends in December and he'll be free, for what I've heard. The twins that are the problem here. After the major they renewed their contracts with Immortals, so maybe Immortals increased their buyout fee then. But they can't change it without the players agreeing on that as well.
As for them being hot-headead kids, I don't think so. They're all experienced players. Needless to say that Fnx has been around since 2003 and he's one of the most experienced players that are still active to this day. Bruno "Bit" was part of the famous MiBr lineup that along with Fnx won the ESWC in 2006. kNg has also been around since the 1.6 times, he didn't have the success that fnx and Bit had, but he has the experience. And the twins they are also around for a while. They used to play 1.6, then they went to Crossfire and when CS:GO came out they were already playing in a pro team, alongside Fallen, Boltz and Steel... So they don't really to prove that they are the next big-thing, they are already well-known in the pro scene.