So I know cross-linking, as in having all your sites linking to each other is bad. But my question is would it be okay if I say, I have 5 websites, and four of those websites all link to the fifth website and that fifth website does NOT link back to the other four? So basically the link juice won't come go in a wheel. Would this be okay for SEO? What if all the websites are owned under the same Google Webmaster Tools account? Keep in mind that all the websites are in the same niche.
That would be ok. It's best if at least some of those 5 sites use different hosting accounts, though.
That's ok so long as the 5th site does not link back to any of the other 4 sites. As GeorgeSenior suggested, it is best to have all five sites on different webhosts. Hope that helps. Have a good day!