I was thinking today, I have 4 zones, roughly 275 feet/zone.

If i have a thermostatic Actuator for each zone, do the zones HAVE to be all the same length, my system has a bypass valve too?

thoughts?

you need balancing capabilities on each loop, otherwise when all are open you would have to equalize loop lengths.

balancing capabilities are standard on any good manifold these days, so equal lengths shouldn't matter at all.