[quote=@Bishop]
[@The Mad Hatter] I didn't say "master" but *add* as in he can have more chakra natures even if he can only wield one. 
[/quote]

Ah, well. That is certainly a possibility, but I would advice against it. 
I believe it is at one point stated that learning to use evne the element that a person has an affinity towards takes years of training - unless you've got five billion Kage Bunshin or are a genius (as is the case(s) with "our" main characters in the manga/anime).
If you (the plural word) want to add some future techniques or something of the like, make sure it is very obviously clear in the CS, so that Halvtand and I can properly judge your character(s) as they are at the beginning - and you are free to make all the changes you want to your future techniques.

[quote=@Bishop]
And I didn't ask, would our characters progress in skill as they adventure, like reaching Jounin level for example? And...hmmmm, do you plan on making us encounter the almighty M.?
[/quote]

Yes, of course you/we get to grow better and stronger over the course of our travels. It mostly depends on what you guys do and want how far you/we develop our skills and to what level. To really become strong, you would, after all, need to train as well as adventure and the experiences we gain will make us smarter and therefore one step closer to stronger.
We do have some plans for who we will encounter, but it all depends on the choices made. I cannot say for sure that we will, but I cannot say for sure that we won't.