I'm thinking mines. Just because I feel like the support weapon + backpack slot is already pretty crowded. I don't see a rocket backpack taking away my love for the Quasar and Shield combo.
Elites will either go after who attacks them, and/or whoever is closest. I would say it is pretty easy to bait them into a minefield, if it had lower cooldown times than the railcannon and laser it might well be a great pick