Flank is the water clan's signature ability - what it does is defined on their identity card (Can’t remember what that card is called, but it’s the one that has the contents of their deck on the underside)The Clan Reference Card. Flank allows damage to be dealt to the bottom unit of the enemy squad (and then upwards) instead of the normal deal damage to the top unit and then downwards.
Abilities without the small flame icon don’t have to be on top to trigger.Correct. The small flame represents a battlefield ability, and that means the ability is only active when that unit is the top unit of their squad. Abilities that are non-battlefield, and generally are related to triggering on summon, on destruction, or on discard, are active regardless of where they are in the squad.
You can only summon units to your home zone unless other game affects say otherwise.Yup.