IMO:
FI Spreadeagle - easiest and if I think about it, I can do it in both directions.
Ina Bauer - Have to really stretch and practice, but I can do it in my dominant direction after a while.
FO Spreadeagle - never had it, I doubt I ever will, but I don't really work on it much.
My preferred direction is with the right foot leading. I am primarily a CCW skater, although I can do some spins and jumps in both directions.
My kids made up a drill for FI spreadeagles:
. start near some marker - a dot, a line, etc.
. Do your preferred FI spreadeagle in a full circle
. Return to the starting point and change direction so the opposite foot is leading
. Do a FI spreadeagle in a full circle.
I've tried it and it really works well - after 3-4 rounds, the weak side spreadeagle isn't as difficult.