I'm going to gently disagree, Mark. I think much of the CAP series is, indeed, implausible, not that I disagree with unlikely. You've suggested the situation yourself, with "...linked together in one family like that." One of the familial twists would go down fine. Two gets a little more doubtful. By the time you add them all up, you've arrived at implausible.
So what?
Is there a single person who reads your stories who thinks that they could be (not necessarily are) real? That these events could reasonably be expected to actually take place some time some where? If there is, that person needs to get a grip.
So what?
I don't read either series for reality. The plot twists and turns are fun to follow and well enough done that while unfolding they achieve verisimilitude. That they won't survive dispassionate consideration is also true.
So what ?
I trust that you write for pleasure; clearly there's no money in it in this venue. We read for pleasure and take pleasure in the characters and the plot developments. If, from time to time, we would like to be one of the characters or share in that life, so much the better. That we might is also implausible.
So what?
I presume you're getting what you seek out of writing these stories for us, or you'd stop. Lots of people are getting pleasure from your work and anticipate the appearance of every new chapter.
That's what counts.
Micky