I'm a huge T-Ferg fan, so I'll definitely be bias here.
-I think he beats Dariush in a 3 round fight by decision or TKO and has a slight chance to sub him in a 5 round fight.
-Chandler, I think if it's a 3 round fight it's a coin flip. Chandler tries to go full power house round 1 and uses the other rounds to grind Tony out with his wrestling. That being said, Tony's striking pressure with Chandler's lack of defense will cause him major issues later in the fight. If it's 5 rounds I go with Tony, TKO or dec.
-Islam, Tony will lose this. Islam is pretty defensively sound and will probably grind Tony out to a decision. I only see Tony winning by a lucky sub.
-Gaethje, I could see the UFC debut version of him gets subbed or TKO'd by Tony. Now Gaethje looks for the counter and acts more defensively sound, but we'll sometimes see the old version come out like the 1st round of his last fight or the 2nd round of the Tony fight. A faster Ferg causes him a bit more trouble, but Tony's best bet is to engage in a clinch with him and tire him out there since Gaethje completely neutralized his pressure last time. I lean towards Gaethje.
-Poirier, I actually think this would be a lot closer than most people think. Prime vs prime this would've been a hell of a fight. I leaned towards Tony because I definitely know this will be a firefight from round 1 to 5. Tony by sub or dec.
-Charles, I could see a prime Tony to cause him trouble. If it's 3 rounds, Tony would probably lose a decision due to Charles crisp striking mixing it with his control on the ground. Tony could get a sub late if it's 5 rounds, probably would've really turned it up in 3,4, and 5. I slightly lean towards Charles here, but Tony could definitely win a DEC or SUB.