It's easy to do all this stuff in PowerPoint, and there are ways to make this
easier.

If you need to bring in lots of photos, you might want to use PowerPoint's
Photo Album feature:
http://www.indezine.com/products/powerpoint/ppphotoalbum.html

And this will help you get your music working across slides:
http://www.indezine.com/products/powerpoint/ppsoundacross.html

I also have some templates on Graduation at
http://www.indezine.com/powerpoint/templates/categories/education/graduation.html

And you might want to add some transparent PNGs on your slides to make them
look scrapbook style -- look for PNGs of framebook corners, buttons, etc.
You'll find plenty of them at:
http://www.scrapbookpresentations.com/embellishments/

I suggest you to understand this first -
http://presentationism.com/how-to-create-worst-powerpoint-slides/
before you make further move on creating PPT for kids.
Your slide layout can not be complicated. The simpler - the better!

J.J. - admin of http://presentationism.com
blog: http://presentationism.blogspot.com