haha, glad to hear it!! I'm really excited to be able to put my own spin on this stuff. As for Guen's child, check out the FAQ on my blog for more information. The consequences of Arthur finding out will depend on how he finds out!
Uh... well... depending on the circumstances, Arthur might be totally okay with it (maybe even happy about it) or very surprised? Beyond that I'm not going to say right now, except to note that Guen will be accused of infidelity in part 6, and the accusation will be weaker or stronger depending on all sorts of factors.
This is correct. There will be some debatable circumstances surrounding the marriage, but they won't be impersonation in this case.
Ah, well, a couple of other elements may be very loosely inspired by Elaine of Corbenic... but yeah, Elaine of Astolat is much more well-known, thanks to Tennyson, so she will be somewhat more recognizable. But I'm also going to be giving the character, and her circumstances, my own particular interpretation, which I'm very excited about.