Si quieres decir "Los dos suenan interesante", pues como lo escribiste está correcto. Cuanto lo que dijo la señora, la traducción literal de "Los dos parecen interesante" es "They both seem interesting." Saludos.

I think the way you said it was just fine. As in, "Yes, they both sound interesting." You may want to use 'seem' as in, "they both seem interesting. Natives use either. Neither is wrong.