You can request, but the visa officer is the one who decides on the duration of the Canadian visa.

Yes

We determine your eligibility by the activities you will be performing in Canada. If your activities do not satisfy the requirements for a business visitor visa, you will have to consider another visa, for example: a work permit.

Your eligibility depends on your planned activities in Canada. The length of your stay does not determine whether you qualify as a business visitor.

Yes, If you are from a visa-required country, you must obtain a Canadian visa before travelling, as entry into Canada requires valid authorization.

Yes, you do. If you don’t, you risk IRCC refusing your application, or a 5-year ban from Canada. 

IRCC assesses each application on its own merits and supporting documentation. Applications are not reviewed at the same time or strictly in submission order, which means processing timelines can vary between applicants.