Hello HugAPanda. I don’t know if you still want information.
Chenghua is towards the north east of the city. This area like many has been redeveloped allot in the last couple of years, including the new music/culture area. There are also a number of large university campuses. It does stretch from downtown to past the second ring road, so that depends on your exact address. Most areas Chengdu districts are as clean as each other, what variations there are, are between neighbourhoods and apartment complexes. I’m fairly sure no parts of Chengdu are dangerous. And there are super markets and open/wet markets most everywhere.
Something you might consider is the most (not all) of the established expat/foreigner activity is focused around the South of Chengdu. Which could easily be 30-60 mins travel from Chenghua, depending on traffic, if that will be important to you