Can I have the first book in my trilogy told from the viewpoint of character A, the second told from character B’s viewpoint, and the third told from both as long as it helps the plot? Or would that be too confusing for the readers?
I’ll do you one better.
Kelley Armstrong’s Otherworld series is thirteen books.
Going in the same order as the Goodreads’ listing:
Books 1 & 2 are from the POV of Elena.
Books 3 & 4 are from the POV of Paige (who we first met from Elena’s POV in book 2)
Book 5 is Eve (who used to babysit Paige, and whose daughter Paige is now fostering)
Book 6 is back to Elena
Book 7 is Jaime (who is friends with both Elena and Paige, and as a necromancer is the only one who can speak directly to Eve)
Book 8 switches back and forth (in 1st person POV) between Hope – a more or less new character – and Lucas (Paige’s SO, introduced in Book 3)
Book 9 switches (in first person POV) between Hope, her friend Robyn, Finn (a police detective), and Adele (one of the antagonists)
Book 10 is back to Elena again
Book 11, 12, and 13 are all primarily told by Samantha – Eve’s daughter and Paige & Lucas’ foster daughter – but other characters have chapters here and there.
How’s that for complicated? But it absolutely works, the books are great, and because she builds up what is, in the end, a large and complicated interconnected cast of characters slowly, through several books, it’s not at all hard to keep track of.
And because Kelly Armstrong knew from the very beginning of the series where it was going to end up (or at least, so she says!) all of the characters had integral parts to play in the penultimate, thirteenth, book, that wrapped up all of the major plotlines while, at the same time, offering each of the characters a way forward into something new.
Many series switch to different protagonists as they proceed.
As long as you properly introduce your audience to them, the first time they show up, and if you’ve switched POVs between books (or for that matter between chapters, or sections, or whatever), make it clear to the reader who the current POV character is (there are various ways to do this), your readers will be fine.
Shouldn’t be a problem at all.
In fact, I have a back-burner project along those very lines.
Book one is at the editor; I want that nailed down a little more firmly before really embarking on the others.
The first-person narrator in the book is an historical figure who I felt best fit the role of narrator.
However, he is not needed in the second and third books, and I gave him a good send-off at the end of the first.
(If he appears, it will most likely be as a cameo – we’ll see what happens).
The first-person narrator in the second book will be a new character, and the first-person narrator in the third book will be his niece, who is a little girl in the first book, a teen in the second, and a grown woman in the third.
Even an average reader should have no problem differentiating between the perspectives.
I've read books where there were as many as 5 characters whose alternating perspectives were shared regarding the same event.
I really enjoyed them, but due to the use of pronouns I occasionally had to look back a little to refresh my mind if I hadn't read for a few days.
This should not be a problem in your case, especially if your characters are a female and a male.
Blessings on your writing adventures!