I did it using two witchdoctor companions on my privateer. Scratchy and the Necromancer pig. The consistently clear the board for me with all their extra mojo echo hits. If one of the snakes has witch hunter then I just buff up the two witchdoctors with all my will buffs and damage buff and by then my hit skills were showing up and I took care of the one with witch hunter. Being a Swashbuckler you will need some healing for you and your team and if you can get valor's armor to protect your best companion, or you. A healing companion will help too. You may need to farm some bosses to get some drops for extra healing and shielding.

Lily Evans on Aug 25, 2013 wrote:

I am a level 64 witchdoctor and have had no trouble on the other ones except for the one where you have to beat Hykssos. His rain of mortar shells is troubling, but the other enemies deal so so much damage. I went in with Kan Po, and he was taken out on the FIRST TURN!
And another thing is that there are 5 of them: 2 archers, 2 flame dancers, and Hykssos, against 4 on my team. It would be possible to actually do if there were 3 of them, but 5? They are just too powerful
Lily Evans, Level 64 Witchdoctor

Yea I learned my lesson quick that my former heavy hitter swashbucklers are getting slaughtered in Aquila. On the sky snakes they took out my Wagu Bull Samoorai in the first round, before I could even shield him. I learned from here to use musketeers and witchdoctor companions and to position yourself well if they have flanking. Just by paying attention to what they can do and making sure you don't offer them any easy hits, can make all the difference. If you have one you really must use then try getting Valor's armor for your Witchdoctor. My musketeer actually has to of them now and she saves her crew all the time with them, plus saving friends too. Once you can protect a heavy hitter, like my necromancer pig, they can do the good damage and still be alive to keep it up.