I do not expect BAF to go for JF-17, even though it is a good fit for their airforce.
1. Awami League, the political party in power in Bangladesh, has never been friendly with Pakistan. In fact one of their consistent policies is to hound and hunt anyone with sympathies for Pakistan. This government's 'trials' & hangings of old JI leaders (more than 70 years old) is an example. Therefore their relations with Government of Pakistan are cold and Pakistanis strongly resent blood-thirsty actions of this government.
2. Myanmar (Burma) has opted for JF-17, and BAF would likely want an aircraft with different strengths. In my view the only affordable Delta-Canard solution for BAF is J-10.
Flanker derivatives would be good for BAF to project its strength far into Bay of Bengal. Financing would be a serious hurdle, even though Bangladesh of today is much more financially sound.
IMV, Bangladesh should spend time and money on the most obvious threat to the country: Rising sea levels. No number of SUs or J-10s can mitigate this threat.