Template customization and shared access

I’m very new to WordPress (haven’t even installed it yet actually), but was hoping that someone could help answer two questions for me about it which would allow me to determine whether WordPress is the software I’m looking for.

I’m in the process of creating a family website. I want to establish the design and template that design (including different templates for different types of pages) and then provide the members of my family with access only to different sections of the website via WordPress. In this way they would be able to update and maintain their own sections basically using designs that I established.

As far as the templates are concerned, the templates I’m interested in recreating are on the website now (though they are early drafts). There is first of all the general page layout (fitzhugh.com/nick/photography.html) and then what could be considered modules such as the design for the photo albums on this page or the type of photo slideshow that is launched when the text link for Weddings is clicked.

I’m mostly trying to figure out whether this is possible and if anyone knows and would be willing to respond I would really appreciate it!

Thank you very much!