How to give ranks commands on my Minecraft server without having to op the player?

I made a Minecraft server and before I post it on the internet I have to fix something, I need to give defaults commands, I have to give them the ability do /nickname. I also can't change their gamemode cause I can only do it with the ones that are oped. I kinda have to fix it, problem is I don't know how. I also need to add the plugin to be able to do /tpa. I have the one to do /tp (still only for ones that are oped so I have to fix that too) but not the one for /tpa. And I made my server on Minecraft-hosting.pro and it's a craftbukkit server. Ok thanks bye~

Added (1). Also, may I know what the plugin for chat channels is? On this server I go on a lot you can do /joinchan (chat name) (example: /joinchan rp) so what is the plugin for it or at least one that is similar?

Sara 01.01.2016

You need the plugin PermissionsEx, which allows you to assign permissions to a default player, you can create groups of hierarchy just like op and non-op but with more control. On my old server I had a default group which allowed everyone on the lowest rank to have access to things like /sethome /home /shop etc, then other groups that had /tp and one for builders to have WorldEdit commands, /tp etc. It's an excellent plugin but can be rather difficult to sort out for the first time, has a learning curve to messing with config files.

As for the chat channels plugin, that one is called Simple Chat Channels

Ducky 01.01.2016