There's a chance, but several things work against it. One, of course, is the salary cap. If there's any chance of Tarasenko playing in the regular season, the Blues can't make the move because while they can fit him now, they can't fit him when Tarasenko comes back, unless they trade someone with a big salary, which would seem to defeat the purpose of acquiring Hall to win now.
Two, the Blues aren't the only team that would be interested in him, so they're not going to get him with a low offer. Bidding will be high. So you can't think a draft pick and a prospect will do it.
Three, any draft pick the Blues trade likely won't be a high one. A 20th pick or worse in the first round is not going to be too appealing to the Devils, when not when other teams will be offering better ones. So you're going to be talking more than one pick, and the players you give up are going to have to be better.
Four, with that the case, do you want to trade a Kyrou or a Kostin and give up years of their playing for four or five months of Hall? Because I don't think you can get him for less than a real high-profile prospect who is ready to be in the NHL.
So sure, he would help, but there will be a bidding war for Hall and it's going to be a tough one for the Blues to win. And if the Blues acquire him as more than a rental, if they agree to a multi-year deal, that lowers the chance of bringing Pietrangelo back to close to zero.
But most of all, if Tarasenko is going to be back in the regular season this season, you can't do it anyway.