There are no commands for most styles built into Word. You could record macros in your template and assign those macros to buttons.

However, if you want to share this customization, you probably want to do an XML customization rather than doing it through the Interface. Otherwise, you will be overwriting any customizations including QAT customizations of people you are sharing it with. This is not likely to make them happy.

Note, you could assign these to a custom QAT in the template that holds your styles. When you create documents based on the template, the customizations will be available to the documents.

Modifying the QAT and Ribbon in Microsoft Word