Pokemon Go legendary mod

my goal is to make a modded pokemon go apk because after explored a decompiled apk i found that the game get the pokemonid from the server then that creates a varible called pokemonid and sets the pokemonid that came from the server as the varible so my idea is just to change it so it gets the id from the server but it has one already set. so if it was set at 150(mew) when you catch it it thinks its 150 so your pokedex get filled, but not with the legement pokemon unless it changes. if anyone whats to help add me on skype sciberrasmaguire or email me maguiresciberras@gmail.com or m.sciberras@bthstu.catholic.edu.au i believe it will work i just cant get the modded one to play it forever logs in