I’m a little confused. How are you displaying ACF fields at all without modifying the theme. Are you already using some type of plugin for this or are you just using the built in ACF shortcode for simple fields.
1 is not possible unless you can modify code in the theme to add a filter.
2 is possible, using jQuery you could get displayed value. But that would depend on how specific the markup is set up so you can get the values. Then you could use some string manipulation to add some additional elements and style these.
3 I doubt this exists
