Can a customer use reward points and wallet balance on the same order?

Yes. At checkout a signed-in customer can redeem reward points and tick Use my wallet balance together.

Wcart applies them in this order:

1. Reward points come off first and lower the amount due.
2. The wallet then covers what's left, up to the customer's balance.
3. Anything still unpaid is paid with the payment method they pick.

If the order is cancelled or refunded in full, both are returned: the points to their points balance and the wallet amount to their wallet.