Actually, the content of headerImage.inc (which will changing to just contentheader.inc) will contain a different header piece (image and a brief description) that will be displayed underneath the actual website header (logo, navigation).
As for the second question, the content could be static, but I would like to keep the option open to have it dynamic just in case the information in that section needs to change.
Keeping in line with my examples, "Whale" will have 10 subpages and will use one of the contentheaders. However, "Guppie" will be identical content with a different contentheader. I guess a better way to explain this would be : "I wish to "brand" each set of pages differently, even though they have the same content".
Sorry if I made this more confusing than it probably is.