ION8N Light Blonde Permanent Liquid Hair Color

I'm using 5nn to cover a box color that came out very copper instead of light brown. I'm 30% gray. Will a 10 volume developer be enough?

I bought 4A medium ash brown and 4N medium brown, I have dark brown hair with multiple warm highlights. will this cover my highlights but not turn red

Do i need to buy a separate developer? which one for ash brown over highlights? want brown not red

So which one of these will give you the lightest blonde?