So playing through the game for the first time and I'm just curious what is the best party that I should use for the last 1/3 of the game (I just "resurrected" Chrono). I am currently rocking Chrono/Robo/Frog which is the EXACT same party that Ryan and Patrick used during the ER, I kinda want to change things up so it's at least a little different experience.

I would like to use Magus but him only having his basic attack and the rest is magic makes it hard to justify him replacing Robo or Frog who can also heal. I personally can't think of a party where Chrono and him can coexist, maybe I'm wrong...

I think I still don't understand the combat system fully, I have no idea which is the better healer between Robo, Frog or Marle, and I also think Lucca is terrible but reading up on some stuff people beg to differ.

So any tips and advice on what party I should use from where I am currently till the end of the game?

Marle is the best healer; Frog is the best because he's a frog and has awesome music, therefore he is superior to Lucca. Magus is a very solid character alone but has very few cross techs, Lucca has some of the best cross techs.

There's not really a ton of hidden depth to the combat system, any tech with a full or heavy group heal is incredibly useful, X Slash spam otherwise. Even on the off chance that your group is greatly weakened it is very easy to heal them to full in a single turn.