it's a little vague what the game counts as a "red" baby but the deck i used was this:
- lil chad
- cube of meat
- lil loki
- spike baby
make sure to not pick up a school bag during your run otherwise you need to have 5 red babies and i think the only other red baby would be double baby.
oh and you can do any level you want just as long as you have all 4 selected, so it's preferable to do it on an early floor and/or act since dps is a little limited with only red babies