Regarding the Ambush Rogue Lore card, does it allow the ambushing unit to follow up and pursue if the original attacking unit dies or vacates the hex he was just in? Or does the ambushing unit just interrupt the attack, attempts to attack, and that's it?
Target melees first.
If its attacker was not killed or forced to retreat, it may then battle back and attack as normal.
In this case, though, the attacker was forced to retreat.