I also have your same problem, read all post but not solve (pheraphs lost some steps)
you for connect in localhost at your ubuntu server use oneother pc ( a win pc?)
when you create a new site, example site1.com
what you write in the url for to see those site?
how modified the file?
the settings in the dns zone and records are how in the images you post here? or have changed something?
is necessary when you create a site1.com also to add something in the dns record? if yes can post the correctly images? thanks