if ur playing scarlet, use a dragon sandwich for roaring moon, fighting for great tusk, bug for slither wing( I wish you the best of luck for that), and possibly electric for a sandy shocks. If you are on violet, then idk.
Shiny eevee, tp to the northmost pokestop in medali, walk behind the restaurant where you fight larry, make a normal encounter 2 sandwich, start date skipping. I got my eevee out break in 7 date skips and got 3 shiny eevees in 40 mins