Hey! Right, the Footprints mission will start once you spot the cat paw prints in front of Jim's house. Also, to start Celeste's quest you have to see at least 1 animation with Lila, and Ellie fixing her bike in the sun dial.
Remember you can speak to Raven on rainy nights.
Lila should be around the Villa Plaza, near the tree, talk to her to star her quest!