Oh cute
that's a high energy mix of breeds, we've had an Aussie, and 2 lab/border mixes, and grand parents had a few Heelers in the past. All of them were quite hyper about fetching , chasing and chewing LOL.
Lots of balls and chew toys will be a big help when he gets older.

It does sound like the food change was too abrupt for a lil one.

And we did this with our pups,

when they wake up - go outside to potty
after meals - go outside to potty
after a drink- outside to potty

into the crate at bedtime. or a small dark quiet room will work.