cashback credited doesn't affect eligible spend. only refunds do.
so you're safe.
Ya. as long as not from refund it's ok, unless some of your transaction is not eligible, eg. Shopeepay Top up.
Previously I saw a post mentioned for refund reflected on the next month you just need to spend more to cover will do.
eg. June I spend $1000 and refund $300 that reflected in July, I need to spend $1000 + $300 to cover.
Not sure does it works as I tried before for period of time, I buy and refund till I lost track.
Don't bother with instalment plans since they are usually not granted any cashback rewards too
Now need to hit their minimum spending to get rewards, Some platform offer you some discount if you use PayNow.
When I got my UOB One card around 9 years ago, they do allow installment to clock as spending.
I got my BTO and bought my appliances with installment to get $300 rebates for spending $2000 installment quarterly.