The World of Avlis

I might roll up an Annihilator. They have Death Attack as bonus feat. If I pick this and DON'T have any rogue levels:

• - will the Death attack work as usual?
  - will I have 1d6 sneak attack?
  - will the DC be based on Annihilator instead of Assassin levels?

- will the Death attack work as usual?

Yes, it just won't stack with improved sneak attack

- will I have 1d6 sneak attack?

yes, you will unless you opt for the option of the avlis death attack see: http://wiki.avlis.org/Death_Attack

- will the DC be based on Annihilator instead of Assassin levels?

That I can't tell you for sure but it should.