Canvas app certainly - the license is included in most 365 plans (business and enterprise) and you can embed these in SharePoint pages.
Not sure about templates, you could browse through the list of templates in https://make.powerapps.com. You might not find anything close to what you're after but it could be a good start to figure out how things work in a canvas app.Your app could use the Naviagte() function to do the work. For example if you have a start screen with a couple of buttons on it like this:
The OnSelect Property of each button can navigate to another screen:
And so on...