Which ending do you want to be canon?*spoilers*

[Chimaera]

I think the Prince stays, and I believe that part of the reasoning is because his sister intended on making lots of changes. I mean just from the one ending you learn that the senate is disolved and that the Commander of the Queen's Knights (which used to always be the Queen's husband) had been awarded to the Queen's brother, not as an accolade in my mind but due to proving his ability and measure. I would think that the Prince (or at least mine) would have stuck around at the very least to get things up and running and also make sure that they were running to his satisfaction. Let's face it, the Prince was really a "people's champion", he really got a lot of people to respect him, and a lot of the people went on to become an important foundation in the new Parliament and other positions of power. Heck, they even changed the role of the Dragon Cavalry and even made it so they would accept women after so many hundreds of years! In my mind, the Prince became the catalyst for a mini "golden age" in Falena and I doubt he would step back from that at least until he was satisfied with the direction the country was heading in, I think the last thing he would want to have to do is fight again. Also, after the defeat of the Sun Rune, I think after seeing his loved ones he would want to fulfill their wishes even more so. Plus from a position of disuading his enemies, why have the two chosen bearers of the Dawn Rune and the Twilight Rune wandering away from close proximity to their runes? I believe that the 3 runes in harmony in the statue could mean that they were meant to work towards the same goal. If that was the case imagine the Dawn and Twilight Runes borne by their respective chosen bearers while the Sun Rune born by Lym in concert together. In other words, it would be a bad idea to invade Falena
So ends my points and conjecture.