Obviously they're a little on edge. Just play like you attacking Lurch was just to say hello. Say that fucking halfling was terribly rude, but at least he won't go to waste now.
Ask them about themselves, what they've been doing. Except Wednesday. STAY THE FUCK AWAY FROM WEDNESDAY. If you HAVE to talk to Wednesday, FOR GOD'S SAKE DON'T TREAT HER LIKE A CHILD. Talk to her like you would an adult. She likes that. Observe the rules of etiquette at the table. Offer them a gift. A lot of posters said get Morticia to speak French - this is a good idea. Gomez will get all horny and then you might be able to go.
Be nice to Lurch, give him a present. He's a man of simple tastes, not a simpleton.
Pugsley is harmless for the most part, he might want to show you his corpse collection or something, treat it like a boy showing you his toy soldiers. Wednesday on the other hand - anything she has is trouble. STAY THE FUCK AWAY FROM WEDNESDAY.
If Fester starts to show you his inventions, and wants to "Demonstrate" them, you should under no circumstances let him demonstrate them on you - tell him you wouldn't dream of begrudging him the first demonstration. When he's... incapacitated... that's your chance to escape.
Seriously, did I mention to avoid Wednesday? Well, DON'T FUCK WITH WEDNESDAY.
Yes, Captcha, if they come out of it with just an operation to make their skin glow, they got lucky.