Gio's velo has been way down the past two years. I'm not sure if his stuff would play in the AL. He's a back of the rotation starter going forward IMO. He has value, but isn't going to be cashing big checks in FA. It's very likely that he signs with the Yanks for a one year deal.
Dallas has been very up and down over his short career and there are questions about his durability. He's definitely not a contender for a long term contract and I think he's holding out for more than a one year deal at this point. From MLBTraderumors: The lefty’s strikeout percentage dipped from 21.4 percent in 2017 to 17.5 percent in 2018 (7.7 K/9 vs. 6.7), and his swinging-strike rate fell from 10.9 percent to 8.3 percent. His ground-ball rate of 53.7 percent, while well north of the league average, also represented a substantial step back from 2017’s 66.8 percent mark and from his overall career mark of 58.8 percent. The biggest problem is that he was expecting a 9 figure deal and held out for one. Now, most potential suitors have moved on without him.