It's a good question, Ryan. My analysis of the situation is that a genuine deal is extremely unlikely, although the various players may pretend that they are willing to strike a deal, and they may even make secret agreements, but this would just be bluffing, and any deal would unravel as soon as Bhumibol dies.
The key reason is that any deal that allows Vajiralongkorn to become Rama X would require the old elite to put total trust in the prince's integrity, and believe that he would keep his promises after becoming king. But how can this ever be guaranteed? The traditional elite hate the prince, and he hates them. The prince knows they have been trying to undermine his succession prospects for many years, and disrespecting him for many years, and he is a notoriously angry man with a fearsome appetite for revenge. He could promise the old elite that he will freeze out Thaksin or whatever, to try to win their agreement to him becoming king, but as soon as he becomes Rama X and controls all the money, what would prevent him reneging on his deal, and bringing back Thaksin, and getting his revenge on the old elite?
Remember that Thaksin can provide something the prince lacks and desperately needs — popular legitimacy. A decade ago, Vajiralongkorn was utterly loathed by the Thai people. Nowadays, he is more popular — he is the only member of the royal family whose popularity has actually risen in the past 10 years, because many Red Shirts have come to believe he is an ally. If Vajiralongkorn becomes king and wants to achieve any kind of popular support, he needs to be allied with Thaksin, to marginalize the traditional elite and reach out to the poor.
The old elite know this, and any promises they make to Vajiralongkorn will be bogus. And Vajiralongkorn knows this, and any promises he makes to them will be bogus too.
So everybody is lying to each other, and preparing to stab each other in the back, while pretending that there is no conflict and that everything is fine.
That is the Thai game of thrones...