P-Perish the thought lass.
Characters from Chrono Cross are similar to Frog and I want to discuss them.
Glenn is a knight and is from a long line of knights, his father and older brother were also Knights. He is young and wants to do his best for Lady Riddel and Lord Viper. He feels he lives in their shadows but he is able to overcome that. He side quest to get the Einlanzer (a weapon that can combat the evil Masamune) also involves ghosts of the past. Since Glenn and Frog (Glenn) have the exact same name, I'm thinking they could maybe be related. Now, Glenn could be a descendent of Frog's or a possible reincarnation. I think this because they are both Knights and have the same name. Silly but I've seen worse.
Turnip is an optional character in Chrono Cross. However, he is more similar to Frog. Turnip isn't human, is blue innate, a knight and talks just like Frog. Also his name is what he is like Frog. So it's possible he was once human as was cursed as well. He could also be a descendent or reincarnation of Frogs. But since he is optional, I find him to be more of a salute to Frog rather than related to him or possible reincarnation.
Pierre is nothing like Frog. But he does posses the Hero's Medal and other hero items. Now Pierre is far from a hero, like very far. But he somehow came to posses that medal. Now and strange as it is, Pierre could have inherited it as a family heirloom. Or he stole it. Though Glenn (Frog) as a human and growing up wasn't too impressive either but it's different from Pierre. So it's possible that Pierre could be related. Or Pierre's Hero Medal is a fake.