Dear piklu99,
First of all as I have seen in your post that few peoples are confusing regarding Hongkong transit visa for Bangladeshi passport holder!! I would like to confirm you that if your carrier is either Dragon Air or Cathy Pacific and if you are transiting through Hongkong to catch up your next Dragon Air or Cathy Pacific flight then you DO NOT need any transit visa if you are Bangladeshi passport holder. But mind it, if your carrier is other than Dragon Air or Cathy Pacific then you must need Hongkong transit visa. To verify, you can call to Dragon Air, Dhaka local office.
Another issue regarding your luggage destination, Well, I don't know whether your ticket is a single one or not? i.e. issued by Dragon Air, Dhaka with a single ticket number? or, separate ticket for Westjet with another number? However, please be informed that if it is a single ticket with single ticket number issued by Dragon Air upto Ottawa then you have to collect your luggages from Ottawa, no option to collect luggage from Toronto. Another major issue is, in USA & Canada most of the carrier except Southwest Airlines charges for each luggages US$25/35 for USA/Canada destinations. So if you have separate ticket i.e. issued by Westjet then they will charge for each luggages. But if you have a single ticket issued by Dragon Air then that means you don't need to pay for luggages, you can carry upto 2 pieces 23 KG luggage for free of cost. Your immigration and luggage checks would be done at Toronto Pearson and you have to catch up your Ottawa flight from Domestic terminal. You may request at Dhaka check in counter to collect luggages at Toronto Pearson and check in at Domestic counter at your own, but I guess they won't allow. My experience is, I had a flight from Dhaka--Singapore--Manila route by Singapore Airlines, I had requested at Dhaka check in counter to collect my luggage at Singapore but they refused to do so, so I had to collect my luggage at Manila.I would suggest you to talk to Dragon Air, Dhaka office for confirmation. Because some airlines have no agreement for internal luggage transfer, specially connecting with low cost carrier and USA/Canada flights. To let you know that I had such a bad experience, my flight route was New York JFK -- London LHR -- Bangkok BKK -- Dhaka DHK by Virgin Atlantic Airways and Thai Airways. When I went for check in, the officer informed me Virgin Atlantic do not have agreement for luggage transfer with Thai Airways so I have to check in again at London LHR airport, So I had to cross the immigration at London and after collecting the luggage had to check in again at the counter. And also it would be a problem for you to declare goods at customs because at Toronto Pearson you have to cross the customs without having luggages with you and obviously no question of declaration at customs as you would travel domestic flight from Toronto to Ottawa!! I would suggest you to contact Dragon Air, Dhaka office for luggage collection at Toronto Pearson otherwise issue separate ticket for Westjet and check in at your own but i am afraid it will cost you more!! Hope you got all your answers.
Regards.