Luckily, there isn't much at Wake to rebuild nowadays. The runway is strictly an emergency landing site for trans-Pacific flights, and the only other facilities on the islands are radar sites for monitoring those same flights. There are still some old missile detection arrays there too, mostly cold-war holdovers that were kept online to provide minimal screening just in case North Korea gets stupid.
It's still technically military territory, but the military completely pulled out years ago. All that's left are some civilian contractors paid to keep the runways operable and the radar installations functioning.
Historically it's a fairly major loss though. Lots of WWII-era structures and markers will be washed away by the floodwaters, and the beaches we fought on may cease to exist. These weren't going to last forever anyway, but it's sad to see them washed away all at once like this.
Wake is built on coral on an ancient volcano rim, so it's going to be pretty sturdy. It's not like a barrier island sand bar.
I can't speak for anything on the island. I've never been there.
But if there was a 20 ft storm surge capped with 40 foot waves crashing across an island with a high elevation of 18 feet, I'm guessing nothing vertical survived.
There may be a few vehicles in the lagoon, but I'm very doubtful any are left on the island.