Question 1:
From the documentation, I see this option:
closeOnSelect: false
This option is true by default, which means that the selection window closes when selected.
So this is a simple plugin call:
$('#mySelect').select2({ closeOnSelect: false });
Question 2:
This question is a bit vague. This is a fairly simple task, but without looking at the plugin files and understanding its logic, it's hard to figure out how to answer - and I don't spend hours. This is something you will have to try on your own, because I personally do not think that you will find anyone here ready to do it for free. He asks for a little.
Take a look at its files and see if you can decide what is happening and try something. People will always be ready to help if you have tried. Good luck.
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