It’s taking me time I don’t have digesting the adapters and decorators of select2, so I’d be incredibly grateful for your input, even pointing me in another direction would be more than okay.
The (Checkbox) Templates In Question
https://jsfiddle.net/rx94kmqu/
An Implementation of selectAll, deselectAll Buttons
https://jsfiddle.net/beaver71/tjvjytp3/
https://jsfiddle.net/hula_zell/50v60cm6/
Disclaimer: All jsfiddles provided above are the generous help of their owners over at GitHub.
EDIT: Thanks for looking at this issue, regardless of whether you provide a solution or not.