To me the cloaked person looks most like the Princess, but Ivona's mom would be believable to me too (considering the type of story it is). I agree with the below the posts that the Knight warming up to Ivona is a bit to quick and forced, but in a story like this it is not outside of the realm of possible.
On the Princess theory, I think if you mix the previous timeline and this one it kind of makes sense. Both Claude and Guise (Gaspal) fought the Demon army in the first timeline. So, they both would be out, as would be their main backers (like Tristan). They also were both technically fighting for the the throne too. With the Princess's claim being ignored, or maybe it is not even possible if they use a Male priority type success system. So, it would not be too surprising that she would side with the Demon King if he offers to make her Queen/Empress.