Awesome Fantasy game

So currently, i am working on figuring out a few things for the game i am designing for "Jake's Awesome Fantasy Game Contest".
The main characters of this game are the Chosen or children of heaven, and they each have a sign of heaven. These signs or marks are: Chimera, Unicorn, Naga, Satyr, Pegasus, Dragon, Phoenix, Great turtle, and Ogre. Each one of these has a special ability/power. The problem is that i have to figure out what those abilities are, but at the same time keep them balanced. They can't be too overpowering or be used constantly. Plus they have to work with the rest of the system. I have worked out parts of a few of them such as: Unicorn- can heal another character. Make a Heart roll, the number of successes equals the number of boxes (either body or blood) that are healed.
The other thing i am trying to work out is what the benofit of have the characters have friendships. In combat i can see it being important as far as overall morale, but in non-comabt situations i'm having a hard time coming up with a reason or benofit to have them. I don't want the game to be all about combat- i want it to be more about the character interactions. So this stage is really important- i feel.
On top of that i have to work out more stuff for the magic system for the game. One thing i know for sure is that the ability to cast magic will work off a skill for the most part. more on this later.