よ works to convey strong emotion here.
よ + a question works here like the English equivalents of !?, ?! etc. These are together called the Interrobang (for more information please look at https://en.wikipedia.org/wiki/Interrobang)
I asked an expert and this is their explanation
'This if i remember correctly Is the explanatory particle. の here is making it more like they speaker wants an explanation or are explaining something. Same with ん except for んです and んだ are a less formal. Here's an article on it since i had the same question not too long ago this helped me
And as far as i know that の without です or だ is just s more casual way of putting it but the の still applied the same way so it is like a のですor んです
And i think ね acts to soften the tone'
You can check that article to clarify your doubt