M.D.
I don't have any advice for you on the biting thing, but it sounds kind of normal.
As for the shower, to me each shower is a celebration of the individual baby...so have at it! No matter what, there are always things you are going to need or to replace or that seasonally are different. I don't think it's tacky at all. Particularly with babies as in life, people will always have their opinions of what you should do and shouldn't...if they think badly of you for having another shower, ignore them! If you want one, have it! They are fun, after all!
-M