mystic expansion doesn't increase the range of hop to ally when imbued on tag along:
hop to ally is considered a separate ability to tag along so it's range isn't affected when imbuing mystic expansion on tag along
buying greater expansion increases the range of hop to ally from 30m to 40m...
Not sure if this has been discussed yet but it's been in the game for a while, this lip on the floor on both sides of the map allows you to place a door on it very easily which can be used to fall out of bounds