Including 2-3 real-life business examples is generally considered appropriate, although the number of businesses that you explore in your response is not as important as the quality of the information used from your case study material and the extent to which it supports your main points. There are instances where you may be able to discuss a separate business per main point, but there are also instances where case study material for one business can help you support more than one of your main points. For example, in a response covering a main point under the marketing topic (for example, advertising) and another main point under the operations topic (for example, environmental sustainability), you may find that discussing a business like Apple can help you support both points.
Regarding your other question, you seem to be on the right track. When taking case study notes against the syllabus dot points, you can list names of businesses with case study material relevant to particular syllabus dot points, followed by notes summarising the main information for each business which, as you mentioned, can include statistics/figures and effects/outcomes. It is good that you are already focusing on five different businesses, and you can always expand your list through research if you feel a particular syllabus dot point may require case study material relevant to a different business.
I hope this helps!