I feel for you, Fuzzy. What concerns me more is how this (and a multitude of other situations which only you know about) will affect you relationship w/ your wife/stepdaughter/grandchild. All families have a different dynamic on how they deal with their emotions. Some bottle up, some let out, some discuss, and so on. I would take comfort in the belief that your stepdaughter will eventually realize she was impregnated by an immature douchebag who sorely needs his ass handed to him, whether figuratively or literally. She will hopefully come around to this sooner than later. When she does though, an "I told you so" doesn't go over nearly as well as "I love you and I'm here for you".
Honesty is the best policy, even when it's tough. Step parents are often targeted by stepchildren as not being the parent, or a replacement for a real one, garnering little respect from the stepchild(ren). As years go by and folks mature, some of the animosity can remain, tension from years past that was never resolved continues to affect the relationship between step parent and stepchild. However, if your stepdaughter is old enough to have a child with the grade A oil changer, then she's old enough to be spoken with like an adult. My advice, voice your concern to her (and your wife) as an adult, and as a parent, don't drag out old issues, just let her know you love her and the child but don't feel respected by the father. The worst she can say is you don't have a clue or your making it up. If that's the case than she has some more growing up to do in my opinion. But she might mull it over and change her mind later (you never know).
And I'm totally with you on the cooking. Let the f#@ker starve. If he's spitting firecracker shrimp out he doesn't know what good food is! (BTW if he was spitting them out because they were hot, they're called firecracker shrimp for a reason!) He's just showing his @@s, and it's a shame that some people over the age of three would think that that is appropriate or humorous.
Good luck, it sounds like a tough nut to crack.
-Tim