I don't believe it matters how many styles are shown/listed. You can modify what is shown/listed using the HOME ribbon and clicking on the downward arrow from the STYLES section (in the lower right-hand corner) then selecting the OPTIONS at the lower right-hand corner of the STYLES menu.

Other posters may offer other options/solutions.

Thanks! For now my plan is just to set the template's Styles option of "Show styles in use". I don't want to bewilder the future authors with long list. And the template, for now anyway, will contain at least one example of each style.