Halloween // Homemade group costume idea suggestions?

Hi everyone, this is my first time using Reddit so please be nice.

My fiance and I decided to have a very small courthouse wedding on Halloween this year (he originally proposed on Halloween 2 years ago and we want to keep our anniversary) and we want to include our two small children (14 month old daughter and 5 year old son) by having all of us wear matching Halloween costumes and going straight from our wedding at the courthouse to trick or treating or whatever events we have going on.

We want something casual that can be easily DIY'd, and we are trying to avoid hats, masks, and face paint so that we're not forced to remove our costumes to enter the courthouse, but we're having trouble coming up with something. Does anyone have any suggestions for a DIY group costume that could fit what we need? It doesn't have to be any theme, but something funny and family friendly would probably be our best bet.

(Also please don't wedding shame me. I wanted to do something low-key and fun instead of spending ing a lot of money and Halloween is fun to me.)