1. What is the lowes level for natu in emerald. 2. What is the lowes..

I guess the lowest level for phanpy and natu is probably about 27. But I really have no idea why that would matter. They are in the safari zone so you don't have to worry about fainting them if you bring too strong Pokemon, you can use breeding or heart scales if they learn moves that you want at really low levels, personally it would make more sense if you asked for the highest level. Chimecho can be found at mount pyre, at the very, very top. And it is extremely rare. I mean at the VERY top and EXTREMELY rare, something like a 1% chance of finding it any given time you run into a Pokemon in the 8 tiles of grass it can be found in.

1. Does it matter? He evolves at level 24. He should be around levels 25-27, though.
2. Again, does it matter? He evolves at level 30, and should be between levels 25-29.
3. Um, at Mt. Pyre? He's obviously not found inside it, and definitely not found along the sides of it. You have to go to the very top of Mt. Pyre, where the old couple are. Once you're there, go down the steps and look to your left and even right. Follow one of those two paths and there should be grassy areas. I reccomend the left area, even though he's still very rare. Like training and raising levels, it takes patience to find Chemicho.

For numbers one and two, you breed and you have them at level 5.
For number 3,im not sure.