Well both 'computers' would have the same IP address without a V P N, if that's what you're asking?
However botting 'safely' has little to do with Internet IP address allocation though, as IP alone is not conclusive. In your situation I'd be more invested in satisfying that 1.) Battle.net accounts share no contact details 2.) said accounts share no payment. Once and only once those two criteria are satisfied then yes, run a virtual computer and a V P N if you are planning to "bot like hell".
Maybe I don't quite understand your question though? I mean if you are planning 'light botting' then just do so smartly and you'll be safe as every other botter out there. Otherwise, "botting like hell" requires extra precautions as per the above in addition to your virtual box and V P N.