I like what you've done here. The only thing though is that I would try and move Meireles and Garreffa as well.
Based on his play this year, Meireles could be among the top 5 OA's next year. He would bring very good return based on that.
Garreffa, as far as I'm concerned, should be moved for two reasons. Number one, he wants to play defence full-time and this coaching staff is refusing to play him there. So move him to another team who will allow him to play his preferred position. (I wouldn't be surprised if a trade is requested for this reason) Number two, if he is a Ranger next year, this coaching staff will give him massive power-play minutes on the blueline. As far as I'm concerned, next year being a rebuilding year, Vukojevic and Sebrango should get all the power-play time in preparation for the 20-21 season.
Go with two more inexpensive OA's to replace Meireles and Garreffa. Also, use next year to work on the OA's for the 20-21 season. Based on the return we got for McHugh, it may be cheaper to acquire a 20-21 OA candidate or two next year. Right now our 00 group is thin. After the Damiani trade, we have four 00's on the roster. With the import G, Pfiel will be out of our plans. I'll eat my hat if Guest is an OA here if we are contending. The jury is out on Rupoli so MacPherson is our only legit OA candidate for 20-21.
I'd also try and add a comp pick in the Damiani deal on him playing an OA season.
I know it's asking a lot for MM to move all four of Yantsis, Meireles, Garreffa and Damiani, but as you said to start your post, "for the fun of it"