Finally beat a WotC Veteran Ironman run. Took so long mostly because I got bored after killing the second Chosen and was just playing really small increments.
Psi soldiers are still as overpowered as always. Took 4 of them into the final mission alongside a Templar and a Sniper. Flawless victory, no damage at all. In the final battle I just put the sniper in the middle of the map and since he had the Chosen rifle alongside Serial + basically every single sniper skill and other stuff like rupture and that one ability that lets you attack again after using a heavy weapon. That one sniper cleaned the entire house.
Using him made it seem like it was a Lost mission, except instead of getting free actions on kills of the Lost, it was free actions on kills of Mutons and Avatars. And if for some reason he ran out of moves, I could use his partner to give him more. And if that still wasn't enough, I could use the 4 psi soldiers to give him more. Lastly, he had that skill that let you overwatch as many times as you have bullets.
It was ridiculous.
I also noticed that the Chosen sniper rifle and the Chosen regular rifle have the exact same model, just different lengths. The Chosen pistol is just a mini version of those. Tsk tsk, lazy Firaxis.