Will this be under google play or just an individual stand by your team?
As what I understand in their project I guess they are independent company and they are not planning in doing a collaboration to google play.
But in their Pre-load Tier1 OEMs it is stated that " other apps store that joined ". So I am confuse what stores that they are pointing to it as google play is a big company already and I am not sure that they will take part in this project.
Google Play and Apple are potential partners in the long run. However, those other app stores that are mentioned are other independent/third-party app stores. There are many like these, from regional app stores (think Yandex in Russia, 9Apps in India, CafeBazaar in Iran, etc..). And then there are others:
http://www.businessofapps.com/guide/app-stores-list/Overall AppAnnie estimates that the annual revenue of the third party app stores matches Google Play's in 2017:
https://www.appannie.com/en/insights/market-data/app-store-revenue-forecast-139-billion-2021/So even without a partnership with other major player the potential of the AppCoins protocol is still quite big.