I'm heading to China for mainly non-mountaineering purposes but will try to do some climbing there as well. Does anyone know if isobutane/propane canisters are available, specifically in the Chengdu area, or are liquid fuel stoves the way to go?

You will have no difficulties to find gas in outdoor shops in Chengdu. Same in any major city in the country. Kovea, Primus, MSR and a couple of other brands are usually available.