Welcome KKE...see my advice below
1.POF i would advise you have a little bit above the tresh hold to account for any fluctuations in currency rates. In USD wouldnt be bad, so you can go ahead with your dorm acc.
2.BC from the national population center will be fine.
3. I would advise since ur GT card has been declined by WES, you get a DD in CAD in GT bank in lagos.
4. Pay slips as an add on are not mandatory, you can put employment letters to support your application.
Hope this helps. All the best in ur application.