Since Bangladesh is fond of J-7BGs I suspect they could go for JL-9s. Buying JF-17s will hurt their pride, they are against all things Pakistan at the moment.That can be a very bad option. Because the relationship of Bangladeshi with India are like servant and master and in that they can let them test fully the product and can make strategies against it.
Makes sense for them to either buy Mig-35s or JL-9s as they operate both Mig-29s and J-7s. Less investment on support and integration.
If India is so concerned with Bangladesh I see them being the only potential export client for Tejas but only through concessions.