Your post is a little unclear at points, did you find your parameters? If so, what are they? When you hit the wrong seed, try using the Adjacent Seed Tool and compare the IVs to see if you're hitting the wrong Timer0 or second. Saving after you catch the Pokémon doesn't change anything, everything about it is set by that point. There's nothing you can do about NPCs except deal with it; however, the top floor of Celestial Tower is NPC-free so you can RNG Litwick there without dealing with them (just make sure to use the right floor's encounter slots).