I have assigned two roles, one for owner, and one for mods; however, not of this works. When I check info, it says that all of the prefixes are there and the permissions are set, but when i type /kit plot (from essentials) then it will say "{USERNAME} was denied access to this command"

I don't know what to do.

Make sure you aren't running any other permission plugins.

The only plugins I'm using are Essentials (X, Chat, and Spawn), Grief prevention, Holograms, LuckPerms, Vault, WorldEdit, and WorldGuard.

Then use verbose mode to check whether you have set the correct permissions

As for prefixes, there is a FAQ entry on that exact subject, make sure to read through it and see if it helps

https://github.com/lucko/LuckPerms/wiki/faq#why-are-prefixessuffixes-not-working