I created a workaround for the lack of a Community page template in the Custom Theme editor in the Help Center. This isn't a complete workaround, but it does provide the ability to change some components to fit your own theme. This example is just for the header section, but could be applied to make other elements on the page.
To only change textual content and formatting, modify CSS as follows:
/* Keep other styles as is, but add the following two which hide existing defined text */
content: "What you want it to say instead of Community";
Obviously both methods can be used to some extent on other items on the Community page, to varying degrees, but I was focused on the Community Heading for my own purposes.