I'm not a bard but I can answer you some basic questions :

you shouldn't let your dot fall as they will cost you 2gcd to refresh, while only one with iron jaws.

Sidewinder will not trigger barrage as it's an aptitude, and until you get Refulgent arrow, empyreal is your best choice for barrage.

Refresh and tactician dump no aggro, they only refresh MP/TP for yourself and teamates. For aggro you have nothing o/