I currently have 4 POV characters, one of which will be very sparsely used. I've known this number will expand by a few characters in Part Two of Book One, but I finally realized that one character in particular will indeed need to be a POV character in Book One after all. Now that I have nailed down his subplot it requires it.
As for the other 3 main characters, I think I can get by for now simply augmenting the description of those passages when the wizard-esque character actually wields power. I still have a bit of experimenting to do with his POV voice, but that is what the rewrite is for. What matters here is adding in the how and the cause and effects of his power usage.
I've decided also to break away from my normal writing mechanism of writing from the beginning to the end without skipping around. Since I have Part One written I already have a framework for the main events that transpire within this section. This will allow me to take all of the chapters of the main antagonist and either rewrite, reshape or enhance. I think the story will flow better if I write his section of Part One out together. After all, barring Chapter 3 of Book One, the antagonist does not come into direct contact with the other POV characters (except for the sparsely used one) for quite a while.
And I shall do the same with the chapters where his daughter is the POV character. All I need to do is keep in mind specific dates on their calendar as place markers for when specific plot-related events occur and the continuity will remain when I take their respective chapters and shuffle them into each other.
Overall, I'm pleased with the start of my redraft of Part One.