As for the ladies, just look nice. You have a few more options than the guys, but make sure it's nothing too crazy, and NO JEANS. I swear I once had a lady walk in for a wake wearing a bikini and a cover-up that didn't quite "cover up." I assure you that anything you can wear to the beach isn't appropriate to wear while standing in front of a casket. You don't have to be a MENSA member to understand this.
Funerals are not the time or place for a buffet
In New York, we can't have food in the funeral home. This isn't just our rule, it's also the New York State Board of Health's rule. Food attracts bugs, vermin, and other unwelcome guests into funeral homes. We know this. The Board of Health knows this. The sign in our lobby is there so you know it.
This doesn't mean "all food except the three dozen donuts and a box of coffee." This isn't Golden Corral. You should be able to handle going two or three hours without food -- it's why most wake times are split up, so you have a couple of hours for dinner in between.