1) Haven't a clue. I started with the Sharpe series, which was plainly under the influence of C.S. Forester, but I don't think Forester had much influence on, say, the Arthurian trilogy. I don't think there was a direct influence on the non-Sharpe books - like most writers I suspect I write the sort of books I'd like to read. Not a very helpful answer!
2) I never think about how I'll be remembered! I'll be dead, so it won't matter to me. But I certainly never think of myself as writing epics . . so I guess the the answer is that I'm a historical novelist pure and simple.
3) The root of the stories goes back to my days at university when I was introduced to Old English poetry and discovered a love for it, and from that sprang an interest in the Saxon period which I've kept up for the forty years since. The immediate spur for the series was the discovery of my natural father (very late in my life to find him, but there you go) and learning that we were descended from a man called Uhtred who had been lord of Bebbanburg, and I wondered how a solidly Saxon family (for such they were) had managed to hold onto their lands through the Danish invasions. The answer to that question is fictional, of course, but the question itself was the immediate spur to writing the new series. As to the conflict of loyalties, it just seemed to me that the Danes would not be understandable unless Uhtred had an affection for them - one of the constraints of writing in the first person. If I'd written in the third person then I could have tackled them differently.
4) Never! Don't plan anything! I just start the book and see what happens. I don't know any other way. But even in starting you plunge the main character into almost immediate conflict - whether moral or not. I'm just starting the new Uhtred and the poor sod has been taken to the mountaintop and offered the kingdoms of the world, but I don't see anything very moral in his reaction. Actually he'd like to take what's offered, but his reasons for rejecting it are, in the end, entirely self serving and trivial. But then, he is my ancestor, and genes will out.
5) Gosh! they do? Wow! I'm not that clever. I just tell a story and, to be honest, never think about unverbalised meanings. I doubt very much that I write under the influence of mediaeval epics because I'm not a great reader of them. All I'm trying to do is to entertain by telling a story, nothing else. Truly.