Looking at the main MQ wiki Spawn.State will return the following.
STAND, SIT, DUCK, BIND, FEIGN, DEAD, STUN, UNKNOWN, HOVER, MOUNT
MQ2Melee can check for Melee.Status of
ENGAGED, WAITING, MELEE, RANGE, ENRAGE, INFURIATE, BACKING, ESCAPING, FEIGNING, EVADING, FALLING, STEALING, BEGGING...