I think one of the reasons they toned up the difficulty on these events are due to the synergy the two unlocking squads have. If they fought a reasonably geared squad meant for those 5, 6, or 7 star characters, the BH would blow them away in three turns. The Ewoks would go and go and go and never give the rebels a chance to do anything. So they had to up the speeds. They had to up the health/damage at lower tiers. A friend of mine has really slow ewoks but they are much better geared and starred than mine(and he has Logray) and he is unable to unlock at 5 stars. The rebels are so powerful that his slow speed ewoks die due to just having circles ran around them. Give the ewoks a modicum of speed and all of a sudden they can interrupt the rebels and start hitting back.