I have known similar 'first move-of-the-day' noises with brake caliper slides. Inspection usually finds poorly a lubed slide that 'releases' after a period of inactivity. Especially if its one of the pair that is sticking, (top or bottom one) as a foot brake holding operation (as we all do) on parking, sets the slide in a slightly skewed position, there is no further movement of the vehicle to 'realign things' until next morning when the wheels begin to turn.
It may not be this at all, but costs little in time to check.
All the best
Steve