What do people reccomend to use in a coop to prevent red mite 😊

[aart]

I've read that whitewashing can help - but is a coating of lime on the walls healthy?

Ehhh, maybe.

Also wondering if painting the coop interior is helpful...?

If the paint fills the cracks and crevices it can help IF you get roost mites as it reduces the place they can shelter.