4th job Single Target DPS

The damage for Buccaneer, is it including critical or without critical?

And which class is stronger? Shadowers or Bucc on bosses?

It's without Critical hits from Stun Mastery, but with Critical hits from Sharp Eyes, if so enabled.

The answer to your second question is complicated. In the best case scenario (for the Shadower), where a Shadower can freely spam Boomerang Step to Dark Sight to Assassinate, allowing the Final hit to connect, a Shadower would win that contest over a similarly equipped Buccaneer. But Assassinate and Boomerang Step come with limitations, so at bosses where they can't use that combo, their DPS falls significantly and a Buccaneer would do more damage.

Also, Apples do push Buccaneers slightly in the lead, even though it means they lose the 20 att from Energy Charge. And while the damage cap is still 99,999, Shadowers get shafted even more.