What Ethlyn thinks of the aftermath: She will wonder if this is what it was like in her homeland when the Evil Dragon God was in charge, and if if this is the kind of thing that's in store for her children now that Evil Dragon God is back in charge. Also w/r/t to the forest colossus having an ocean cousin: Michael Scott says it better than she can.

How the Chosen should deal with the Rumpiturians?
She... doesn't have all that much compassion for them, sadly. Ethlyn would like to punish the people who specifically did the kidnappings and she would personally rather leave them to their fate--the only thing that gives her pause is the thought of the sea monster turning its sights on Aldrip once it's gobbled up all of Rumpitur. But while she would like to solve that problem, she's not willing to work with (or even speak, probably) to the Rumpiturans.