... Bother making a Xenon?

Go with the bottom build, DA card effect is exactly the same as kanna. Possibly replace Canoneer with TB cause, if you want -4% exp loss, just go farmville and get a grade B skeleton, because there is a limit on the littlest you can lose apparently. Somethign like 5%.
I do believe that da's only get minimum crit from their mastery, So the hayato card well boost your damage overall than +40 str from kaiser. Its just more of a given that if your going to get the hayato card, you should get the MM card, but seeing as how there is no room and you want the pirate set. Possibly switch DS card for Marksman, but you stated you dont want to level another adventurer so thats not an option. Then it comes down to 4% cool down reduction vs 3% status if you possibly want to replace the ds card. TB is a pirate, it counts toward the pirate set

Any status resistance helps, honestly, and thus I would like to keep DS card rather than add in Merc. I could replace Kanna with Merc once my DA is 200, as well. As for Cannoneer, he's simply there to finish the set. I could replace it with TB, and prob. will.

So what you're suggesting is:

TB/Xenon/Mech
Hayato/DRK/Aran
DA/DS/Merc?

Possibly?

It's less worth it because of the ease at which you can get to 100% (in GMS). After that any extra Ignore DEF, for example, the Pirate Set, is worthless. It'd be more worth it if we did get the Ignore DEF change because you could never have 100% Ignore and the more Ignore DEF you'd have, the better. Demon Avengers get 30% base, you can get 30% from the Leafre set, 2 15% Ignore DEF Nebulites, and a level 1 or 2 Luminous Link gets you to 100% or 105%. That's not including the 30% Ignore from Execution. And then there's the additional 30% Ignore from Armor Break, which I believe, like Threaten, Cry, Legendary Spear, would be multiplicative with your other DEF ignore sources.

Alright, I'll give you that, although I'll probably be using the Clocktower set. Regardless, I am at over 100% once I have Execution, however for training to 100, it still means faster training. Also, not every class is as blessed as DA when it comes to DEF ignore. My submain will also use these sets, more than likely.