After initially trying to add a tab container to the Splash widget, I started working on a widget that would open after the user agrees to the terms and conditions on the Splash screen, but would also be accessible from the header controller later on in the program or if the Splash screen is bypassed altogether. The end result was a modified theme and a "Welcome" widget.
Much thanks goes to Robert Scheitlin, GISP for his generous help and ample patience.
Creating a document where this widget/theme hybrid would be more visible was suggested by Rebecca Strauch, GISP. Thank you.