What happens when the Hunter’s Familiar dies? How many squares is the Familiar’s Movement?

When the Hunter’s Familiar dies, it will not take actions or be involved in an encounter until the next time the Hunter activates their Wings of Blood Action Skill. At the time, the familiar is brought back into the action in the Hunter’s Square.
The Hunter’s Wing Familiar has a Flight Movement of 4 Squares (as listed on pg. 125 in the Wing stat block).