Array expansion and plugin ip's

[sentein]

I am looking into my optionsfor NAS and i had a few questions before i erase my current setup to try this. I have 15tb of storage space and will be needing more soon. With unraid can i expand my array by adding drives without creating a new volume or without erasing what i already have?

 

Second question is about the plugins used by unraid. I have had very little experience with true NAS headless solutions. I ran freeNAS 3 years ago for about a month. In freeNAS each added plugin/jail gets a specific ip address all their own. This is honestly critical to my network setup. My router is hooked to a vpn for a select number of ip on my network. I can specify ip but not port number. So i would need 1-2 ip from this server that are specific, so here is my question.Are all plugins on the same ip with different port numbers or can each plugin have their own ip?

 

I have tried looking to no true answer on these. Any help is appreciated as my "new" rig should show up this coming week.