[@HylianRose]
Well honestly I was thinking that these two powers are very large powers to have.  Water is already a very big element to harness so for her to have healing powers as well seems kind of too big.  
As for your second question I'm a bit confused as to what you mean but I can say that if by skills and abilities you mean the ability to heal of take control of water (whichever one you choose to use) I can say that over time she won't be able to obtain an extra power, only nurse the power she already has.
I hope this is clear, otherwise send me another question!