Well, since Littlefoot would be at the front door (presumably knocking or using the doorbell) and not the back window, and he has a friendly face, I would answer the door how I normally do: Peek through the peephole first, then crack the door open and stick only my head out

.
Since it is Littlefoot, I'd invite him in and let him invade the fridge, which is full of fruits and veggies

. Then I'd sit with him and listen to his stories about the many adventures he and the others had been on, and then share my stories with him

.