Technically you're correct most scholars conclude the gospels fall under the popular biographical literature types of the time period if memory serves.
They probably needed to fit on a single scroll and that's why you may see the authors of the gospels take acceptable literally shortcuts. Time compression and other such acceptable techniques of the time would have been employed to save space.
For example - one gospel author will say Jesus cursed the fig tree they went off to preach for the day. They returned the next morning and the tree had withered.
Another will say Jesus cursed the tree and it withered.
I think however when they were directly quoting the words of Christ they would have taken extreme care to convey the message correctly.
I'm not opposed to the idea of the Q document hypothesis either. Matthew for example might have been an excellent candidate in a role transcribing Christ's original sermons. Can't really back it up. But it's a strong possibility I feel.
I have enough information in this area to satisfy myself. I've left this particular field of study behind some years ago having been fully convinced of whatever questions I needed to answer.
But I'll say it again, spend some time maybe a month or so soaking up everything you can find from Dr. Gary Habbermas.
http://www.garyhabermas.com/
Nt wright is another worthwhile endeavour in this area. -
http://www.ntwrightonline.com/
Or a personal favorite of mine Mike Licona -
http://www.risenjesus.com/
I'm not sure I would go browsing in the area of non Christian new testament scholarship without appropriate adult supervision. If I want to research a non Christian new testament scholar the first thing I'll do is look for a debate between the heretic and someone I know I can trust. Most of their lies will be exposed uncovered and explained in the ensuing debate. On the other hand if you go see listen to these people directly, they'll run riot all over your faith.