I’m a friend of semantic HTML and progressive enhancement, and that means that something should work at least in a basic way without JavaScript in the first place, and then it should be enhanced with JS. That means, by default, the testimonials could be displayed below one another, and the whole “slider” and “active class” and “pagination” thing would be created with JS, so ACF has nothing to do with any of that.
These empty spans and list with “dots” have nothing to do in there, this should be generated by JS. Since WordPress works with jQuery by default you could use a jQuery slider plugin such as Cycle; this will generate all the functionality you need.
