Google Translate guessing-
Some QR Payments like PayPay & LinePay reward points issued 1- 3 months later
Seven-Eleven, FamilyMart, Lawson, and Ministop will immediately rebate 2% off transaction. FamilyMart fine print states that overseas credit cards will be rebated 2% but not covered by the initiative's funds and WeChat + Alipay not eligible
https://www.family.co.jp/company/new...190830_02.html
Not all cashless methods at all stores will qualify for rewards
https://cashless.go.jp/consumer/branches-typeA.html
Applicable Credit card rebates are domestic issued.
tl;dr: Suica/Icoca/IC transit card better chances of timely rebate for tourists when buying from a qualifying small seller or combini without meeting tax-free tourist minimums when this takes effect until June 2020. Seems YMMV.