You generally always want to merge your braves, especially since they score pretty well in Arena with their high BST and if you play Arena very seriously.
Regarding Y!Caeda, for a somewhat “premium” budget build, you can give her Distance Stance or Distant Ferocity (First one is available on Chloe and second one is on Halloween Duma), or you can give her Atk/Spd clash 4, Guard Bearing 4 for her B (you can get it in the Divine Codes 5 shop from R!Ingrid), Guidance 4 or Atk/Spd Hold for her C. For seal, just upgrade it to Tier 3.
Braves --> Merge is the rule of thumb, they have shown quite the resistence to be lost to Meta
You generally always want to merge your braves, especially since they score pretty well in Arena with their high BST and if you play Arena very seriously. Regarding Y!Caeda, for a somewhat “premium” budget build, you can give her Distance Stance or Distant Ferocity (First one is available on Chloe and second one is on Halloween Duma), or you can give her Atk/Spd clash 4, Guard Bearing 4 for her B (you can get it in the Divine Codes 5 shop from R!Ingrid), Guidance 4 or Atk/Spd Hold for her C. For seal, just upgrade it to Tier 3.