Are you really going to live with your in-laws?

[jolenta]

Why are the newlyweds so surprised to see their in-laws at their own house if the new couple has to move in with them? Or are the in-laws the ones who don't own a home yet & are moving in with the newlyweds? Also, in the last scene the couple looks like they're about to be attacked by a giant mountain lion. I think it would have been funnier had they been more subtle but since I don't know who's moving in with whom, it's hard to say how that scene should have been acted.