I believe that they have the plans for the temple and I thought I read that they even have it already prefabbed. They have all the utensils that they need for the inside of the temple and they have the priestly garments and have been training the Levite priests they found. From what I know they are only lacking the spotless red heifer and if you look at my post above, they are working on getting one of those.
I believe once they get that spotless red heifer, we are gonna see a push towards building the new temple. Right now without that heifer they can’t sacrifice anything anyway.