Dana White says fight island will be ready sometime in mid to late June, as per his interview with BT Sport, here
Also, as per his interview with Sport’s Illustrated’s Greg Bishop, here’s what Dana White had to say-
The infrastructure is being put in now. This place is literally going to be a UFC Fight Island — just like our training facility in Las Vegas, with the UFC Apex next door that can host concerts, comedy, stuff like that. That’s what we’re doing on the island. We’re designing and building it for people to come in and train, with rooms and things like that. The whole island will be laid out just for fighting. … Everybody has this image in their mind of Fight Island, like something out of a video game. It will be a lot more modern than that. There won’t be tiki torches or any of that s—. … We’re gonna use it a lot until the world gets normal again. We’re gonna need it for our international fights — a place where people can fly in and out easily, without needing a bunch of visas and red tape.