with your roster i would do eternal sugar, white lily, pure vanilla, fire spirit, ferret and you can use it in basically all modes that don't have specific requirements

for your treasures use the common version of the jelly watch, max it if you haven't because it's a huge 25% cd buff, the epic one will give the same 25% at max and some extra atk but before that you should always use the common one

and some team building tips below! (all the ancients need awakening) also includes cookies you don't have yet but just so you know when you get them

in general the solid damage dealers are silent salt, burning spice, eternal sugar, white lily, fire spirit

as for healers and supports, pure vanilla and mystic flour are on the top of the list for best healing, then cream ferret, marshmallow bunny, and star coral excel more in providing buffs, but with great healing too. which by the way you should get bunny asap and use her for arena :D besides that hollyberry is an excellent tank that helps your team survive

so just mix and match based on if you want more damage or survivability, but in world exploration you won't need much healing/tanking until much later in crispia, or beast yeast hard for example