put mantyke, buizel, and overquil in your party, go through the oceans gate (the thingy by gyardos spawns) during morning i think iirc, and then you'll get a popup
then go seafloor cavern or w/e the cave is called to the north and get your manaphy
not really, i kind of just suffered and decided to search for a bunch of stuff at once (bonsly, cleffa, cherubi, eevees) and a couple other stage ones and i would just swap maps and check them every once in a while
cranidos - distortion zones
turtwig - second map all the way bottom right the small little lake
cherubi - kick the trees in coronet highlands in fabled spring / primeval grotto by the lake. the shaking trees that spawn burmys can span cherubi in those trees.
zorua - underground ice cave hole...
i believe you have the leave the map to completely reset it, or change the time but its not always consistent. can also just catch pokemon in the area you want somthing in then wait like 5mins and go back there for respawns
so like how you catch 10 bidoofs or whatever to fill out the page for the pokemon or whatever, you gotta do the same for those 3. so read the things you gotta do on its page --
use its special move like 3x each on strong or agile based on what the card says