If I were playing the game, I would go with avengers on account of not being good enough to manage a strike crew of DTs and properly macro at the same time; I would welcome being able to have a fire-and-forget infiltration group that doesn't need exfiltration. (I also think the recall ability is very on-brand for Protoss and therefore like it thematically.) However, it doesn't sound like that's a problem you have (except for the screenshots).

As far as abilities go, I'd say chrono surge and orbital bombardment.