emsquared says:
We'll be using Point Buy for attributes.
Also, I do have to say wulfnor, that the idea of having a canon(?) character in the game as a PC makes me uncomfortable, as I don't know what your expectations are for that, or what liberties you might think that gives you.
If you want to do this, do not expect to have any special knowledge - even if it's knowledge that said character "should" have based on their canon (particularly regarding what's really going on in the background of the world, i.e. the canon meta-plot, for instance he won't know or believe Sauron is in Middle-earth nor who Aragorn really is), and especially don't expect any mechanical benefits - no advantage on checks with someone your PC "should" know, no Sanctuary in places where they may have lived or have good friends according to their canon.
Basically, you can play a character named Halbarad, son of Halbaron, but play them as if nothing you know about them as a Player ever has or ever will occur in this instance of Middle-earth...
My instinct is to say, no, but I'm willing to trust you to not try to take advantage of it.
Also be aware, AiME campaigns can easily span many years, so you very well may end up altering the story of Halbarad and never doing the things he does.
You can use the 5E character sheets and just add the AiME stuff in Notes section, or you can use the "Custom" option, which is just a blank sheet.
Well it's been fun, best of luck with the game!