Questions about the ending of Future Redeemed

Huge spoilers

Hi. Just finished FR today, and though I loved it and the entire trilogy, I have many questions unanswered, or I’ve failed to draw the conclusions. But could you help me with these questions I have please?

-Where is Mythra and Pyra? It’s not like they could’ve just died, they are a part of the trinity processor.

-Where’s Fiora and the others from the first game?

-Why and how would Melia and Nia be queens? It just feels like a random cameo without any explanations. Base game left it out, so I was hoping FR would clear it up at least.

-Most annoying of it all, FR shows two worlds becoming one finally. But it’s a prequel to the 3rd game. After Z gets to create this artificial limbo Aionos, in the end aren’t there two distinct worlds now? Noah and Mio’s worlds?

Are these things canonically vague forever now, or have I missed something?