Not to avoid the question, but you have a full, balanced group of almost max level characters, so you can pretty much do anything if they're well played (maybe tricky if you're boxing them all). I would basically work my way up the list of bosses (someone just started a thread on that here:
viewtopic.php?f=1&t=53 ) and when you start having trouble, you'll know that it's time to gear up a little or work on your strategy. Just guessing, but you could probably clear all of luclin just gearing up as you went, if you could manage the logistics of the fights. You could probably take a decent chunk of pop bosses with a few strategic upgrades.