Doesn't the bride/bride's family have any say so on the planning? Or is it the reception (walima) given by the groom/groom's family that you are concerned about?
You're content to leave the choice of your mate up to others? :hmm:
My thoughts on your issues/questions:
Photography: I believe it is quite subjective and so is there really such a thing (person/organization) as the best? You/your family/friends in Dhaka/Feni should ask around for event photographers/videographers who are freelancers and not yet earned a reputation for which they can name their price. As there are so many TV channels and TV drama (serials) production companies, there are many who work in those companies as photographers and moonlight as event photographers. I have a couple of friends in the business whom I could ask for reference, if you like.
Banquet: AFAIK, it is really up to you as to how you set the dinner to be set up i.e. whether a buffet style or a sit down dinner served by waiters. I've been to wedding receptions in Dhaka where some had traditional sit down dinners while others had buffet style.