Hi currently I’m looking into installing MIAB on my current server where already VestaCP is installed although I set it up to run with an external DNS provider (CloudFlare). Thus I wonder how do I install MIAB without requiring the use of a its own NS, is it possible?
You cannot install MiaB on a server which already has VestaCP. The VPS must be a clean minimal install of Ubuntu 18.04 LTS Server edition.
As for the DNS question, yes it is entirely possible and commonly done. All DNS entries which you need to enter into DNS will be found in the Admin area on the External DNS page.