Technically Vegas could still trade Dadonov to free up cap space but anybody involved would not be eligible to play the remainder of the regular season.
If I had to guess what his ten team NTC looked like:
high tax + team with cap space: Anaheim, Los Angeles, Montreal, New Jersey, San Jose
non-playoff team with cap space: Arizona, Buffalo, Columbus, Detroit, Seattle
Sometimes players will leave off a capped out team like Toronto since they know there's no way they could fit them under the cap. I think Alex Goligoski's NTC got leaked and some thought it was a strange that he listed Los Angeles but not Anaheim. Some thought that it meant that he didn't want to live in LA but was okay a little further south, but it was because the Kings had cap space and a need at LD whereas Anaheim was well-stocked at LD and weren't really a logical team that would trade for him.
Vegas might be out of dance partners. But hypothetically, some team might be able to leverage this into a nice pick but at the cost of paying Dadonov 6.5 million in real cash next season.