I do aggree that we are here to grow (through testing/trials and experiences) and learn who our Creator and savior is and to be in fellowship with him. You'll have to forgive me though, as I am not an apologist for the Christian Evangelical faith, rather this is my humble opion.
As a believer, I always looked reverently at God as my heavenly father and believed that he created us because he can, becuase he is so unimaginaly creative and on a much larger scale for the reason we have families and create families, out of an expression of love.
I can honestly say that I have never really thought about it other than have the understanding of Gods nature be as partially described above. I am not aware of any specific doctrine so to speak on this topic, but I am the wrong person to ask.
As for you second question...wow. I don't really have any profound thoughts on this other than I believe that God is the same yesturday, today and tomorrow and that I understand that he has always been a creator and holy supreme being. I have not looked into it any deeper than that.
These are all standard Mormon beliefs- straight out of the missionary discussions and mormon.org and lds.org and Gospel Principles and Preach My Gospel, which is what the missionaries use in their discussions. Those sources are compilations of Mormon doctrine.
For a quick summary, go to page 48 in the manual quoted here:
This will take you to Gospel Principles