Just to clarify since there are multiple questions.
1. Amazon pay balance works for monthly installment payments
2. Always prefer Gold Glow scheme i.e the weight based scheme
3. Your first installment would be at the physical store
4. You can use your amex card to pay even for the first installment. Malabar doesn't charge any fees , atleast for me I haven't seen any charges tagged on.
5. The scheme is already a great discount, so don't expect more discounts on top
6. Amex card can be directly used on the malabar app and it fetches base reward and is also counted towards milestone rewards.
7. No , Malabar doesn't pay for the 12th month , grt and tanisq does it I think but need to confirm.
8. Do not purchase Malabar gold vouchers from amex gyftr, it doesn't work for scheme payments.