Ok, so I finished a book earlier this summer, and I started on a prequel of sorts for it. What happened was I had this weird dream that consisted of an alien planet that, when encountered by humans for the first time, was a devoutly Catholic planet. So I started with that basis and created a first encounter novel of poison, revenge, and a multi-planet alliance. That was the first book. While I ended up giving hints that the Mirellans (as I called them) were Catholic, I did not explicitly come out and say it.
So the second book I started is an explanation of how that occured. But what I'm trying to decide (and it's nothing that needs deciding right this second, as I still have a ton more writing to do before I get there) is whether or not I should bridge it to the first by having characters from the first book in the second one. The thing of it is that the 'prequel' is set three hundred years earlier than the first book, so the characters wouldn't overlap. I did however, end the first book with the main character telling someone the story that I am telling in the second.
The idea for the return of those characters is threefold: 1) because Leah, the main character from the first book is researching the events of the second book to learn what Earth had said about the encounter; 2) because Leah's adventures are going to continue in the third book, and I think that something should link the three besides being set in the same universe; 3) because what happens in the second half of the 'prequel' sets up the events in the first book a bit more.
(Does this make sense without me telling what the story is?)
So the questions I have are : can I insert these characters without making it too obvious? Is there any easy way to transition to them? Should I keep this "prequel" the second book, or make it the first one? And if I do switch the order, do I really want to add in the future cast?
Any advice would be helpful!