I have a feeling that with all this SEO stuff built into Genesis, that having All In One SEO installed would be overkill.

Actually, feel free to install AIOSEO or Headspace2 or SEO Title Tag ... Genesis will detect when these plugins are active, and any duplicate functionality will be handed over to the plugin. For instance, if AIOSEO is active, you won't see the in-post SEO options that Genesis normally provides. Or, if you have SEO Title Tag, Genesis won't generate your Title Tag for you ... PLUS it will actually output the SEOTT function to the proper location, so you don't have to modify the header.php file.

Genesis does not come with any child themes

There is actually a sample child theme available in the Genesis forums for people to download and try out. It's not much, but it does give you something to get you started creating your own child themes.