Li, Xia; Li, Jinfang; Luo, Yongxian. A Grammar of Zoulei (Southwest China). 2014. hh:g:Li:Zoulei
It's unclear whether /x/ is a phoneme or a variant of /χ/.
/ə/ almost never occurs without a coda. /ɿ/ only occurs after /tsʰ ts s z/, but contrasts with /i/.
Diphthongs can probably be analyzed as sequences of glides and vowels, but /ie/ is realized with /i/ as the main vowel.