Much wasn't all that far from the door, wandering the parsonage on his hands and knees trying to get a child's eye view of the place. The knock at the door was so obviously a kid, for half a second he thought he'd imagined Will's baby into existence and onto the doorstep.
Obviously the next most obvious scenario was that it was one of the kids come round early for the Easter egg hint. Probably Pippi. Girl was absolutely diabolical. He'd hidden eggs in places he'd never even explored before, just to give her a challenge.
But as Much crawled closer to the door, he could sense the immortal on the other side. Walking suspiciously on his knees, he poked open the letter slot and looked out, right into Ella's eyes. Well! That was okay then. "Hey kiddo," he grinned, wiggling his fingers out the slot. "Hey Clio! One sec..." He reached up and unbolted the door, having to really stretch because he was still down on his knees.