The likely place those shorts and shirt will be found are in those dumpster remains, IMO.
Possible scenario: Baby dies of poisoning, vomit on shirt and shorts. Mom freaks out, calls accomplice. He comes over, they plot a kidnapping. He first walks down the street and burns the clothes in the dumpster, as they have evidence of the cough syrup. Then he sends a text saying "Ready when you are" etc. and he walks back, walks through front door, goes to baby's room, picks up baby, walks out front door, is seen by neighbor carrying baby in diaper on way to disposal site.
MOO.