About the last panel:
そうだね in this particular case is "Let's see", not "you're right". But if you just change it into "That's right", it will sound way more natural.
BTW, does he really believe he can stop a civil war just by giving in? Dibel's faction is already hostile to the current royal family and its faction. The very moment he ascends the throne there will be either an uprising or a purge.
@TheDerangedOne Mewtwo only knew how to because his mind was shaped by the researcher's daughter's copy while in incubation. And even Pikachu was actively using puns (which definitely require use of language) as a method of ommunication since episode 1 of anime.