This is something that I whipped up over a long and painful time of looking for not succeding and doing over on a trial and error bases. Note this is for only after manaphy rejoins you and you have secret slab,mystery part.This contains over about 15 legendary pokemons locations.
You should carry a amber tear/golden mask/friend bow and also have a lvl 100 if possible increases chances of recruiting
Higlight to see the places.
Ho-Oh Mt.Mistral floor number 19.
Celebi Mystifying forest floor number 10.(for time only)
Darkrai Mystifying forest floor number 13.
Lugia Surround sea floor number 19.
Entei Deep dark crater floor number 10.
Suicune Marowak Dojo Final maze floor number 29.
Raikou Concealed ruins floor numbers 20,29.
Mewtwo Dark crater floor number 6(for darkness only)
Zapdos Amp plains floor number 7.
Moltres Marowak dojo final maze floor number 40.
Dexoys different forms for different locations defense for temporal spire floor number 6, speed temporal spire floor number 5, attack temporal spire floor number 7, normal shimmer hill floor number 17.
Jiarachi Marowak dojo final maze floor number 23.
I'll let you find Latios and Latios and a few others on your own I mean what fun is it if I tell you all the locations.
Post here if you would like me to PM you the locations of the others I won't show all to people who don't want to see.