Approach to creating a site with this structure

you could make category for each family (name), and a (sub)category for each region, and then assign custom templates to each category using category templates plugin. or – in case you want to use pages instead of posts/categories – then you don’t need this plugin but instead just create additional page templates for each family..

both ways will give you a box when you go to create new post / new page which will be on the right side – and there you will be able to choose a custom template for each post/page.

for gallery, I recommend NextGEN – you can create separate gallery for each family, and assign them (gallery categories) to post categories or pages. NextGEN will give you lots of options.