About the insult to royalty, Evan already said the matter will be left for the King to decide, so it's now the best for everyone to just wait for the adults to settle this matter. Skipping the king and decide on their own right now should also count as insult to the king's authority.
Love how the job is spread. In the novel, Serena did almost everything.
- Reminding Einrich that the engagement is made between family is handed to that nameless knight. In the novel, they are only afraid but couldn't follow Einrich's order because they know better it will ends up badly for them.
- Pointing out Einrich being inferior to Evan is left to Rosemary, which has more anger in it from what happened. In the novel, Serena only say that to provoke him to do violence, to make an excuse for Evan to step in and end the little show.
I mean compared to both serena and prince evan both of whom have reincarnated and thus are mentally older than their peers he is just a kid.
From the previous hints at least, he doesn't seem to have complete memory like Serena. His personality is more from his growing up as a prince.
Giving him a care about his brother is also nice. In the LN, he's less forgiving. He knows his brother will be a rival for the throne, that his brother's faction had attempts to end his life, so he is just alright with taking available chance to remove threat once and for all.
What the fuck is that warm look for? You better beat the shit out of your braindead brother, no "oh he is just a kid" bullshit.
I think I mentioned it before, the author seems to put the children's action from influence of their adults. Children shouldn't care about politics that young, but there are princes who were raised up by ambitious mother who made it like their only worth is to be the best and take the throne, so that's the only thing they believe is right.
Maybe Evan just feel better seeing his brother can think of someone preciously. The old him wouldn't care, because he thought being a prince made him above everyone else.