The Muslim population in China is highly diverse. Not only does it consist of more than a dozen different ethnic groups, but their level of adherence to Islamic practice also varies significantly. Many are Muslims in name only. Due to the special privileges offered to ethnical minorities many people are inclined to register themselves and their children as Hui (Han Muslims) for the slightest of family heritage.
Generally speaking, only the Uyghur and Hui people in Xinjiang, Qinghai and Ningxia follow Islamic protocols strictly. Even that is not universal, as a significant part of Uyghur population is also highly secular - obviously an Uyghur communist party member cannot be a loyal Muslim at the same time. So the real impact of the halal issue is fairly small. As the PLA only drafts a very small portion of suitably aged male every year, there is really no reason for them to forcibly draft anyone who cannot adopt.
As far as I can tell, the actually policy in the PLA is one of loose accommodation – we don’t serve you pork, but don’t ask for the kitchen or the food processing to be strictly Halal. Halal cafeterias are sometimes available in big institute such as a high-level HQ, a main base or an aircraft carrier but that is more a comforting and PR thing.