Integrating WeChat pay into Android app (Java)

Question

I would like to integrate WeChat Pay into the app. The app will be used mostly in mainland China. However, users outside China can use it as well. From what I found so far on the integration:

1. I could go approach one of the listed service providers in my country, Malaysia.
2. Register on WeChat Open Platform with a verification fee of 300 CNY (within China) or 99 USD (outside China). (Correct me if I am mistaken on this)

Would option 1 have any WeChat pay limitations to the users (from China and/or outside Malaysia)? I assume that Malaysia users would have no problems accessing WeChat pay.

Are there alternative ways to integrate WeChat pay? Thank you in advance.