Are Elfinkazi considered to have moved when the unit they are roosted on moves?

Elfinkazi move with the Unit they are perched on. This will trigger effects that happen on Movement, like Toxic Secretion, but does not count as the Elfinkazi's move for the Turn. An Elfinkazi may move after its roost. Importantly, an Elfinkazi does not gain Movement when it moves into a roost, it only changes its Movement stat. If an Elfinkazi moves two hexes from its roost to move onto a Regal Lookout Spire and gain 3 Movement from Roost, it has already moved two hexes this Turn so it can only move one more Hex with its new three Movement stat.