So you’re doing the right thing in terms of focus feeding one of each colour.
My advice in terms of who to focus on:
Finish Marjana to 3-70 seeing as you spent the materials on her…
Then finish Sumitomo to 4-70 for the same reason
Next I would prioritise Guardian Falcon then Wilbur then Boldtusk (then BT Costume)
Guardian Falcon will work nicely with both Marjana & Sumitomo. Plus is great for titans. Wilbur is an all round star & BT is one of the best healer options around (only red one other than 5* event heroes…)
Pause Vela. Leave her be for the now… can come back to her later…
You got Grimm & Boril & Kiril ascended which is a good start.
Next would be Sonya (and costume) then Triton.
Then come back round and work on Vela. Definitly Vela over Perseus in terms of the first Blue 5*
Finish Hansel… He’s so close & you spent the mats (GREAT HERO!!!)
Same with gobbler… not great but you spent the mats so finish him to 4-70
Then I suggest Caedmon then Melendor (and costume) and finally Gaderius.
Your only other 5* green option is Horghall who isn’t fantastic… I wouldn’t bother levelling him until you got 11 Tonics waiting and no other 5* options… In the meantime just keep going with 4* heroes (Little John, Caedmon #2, Skittles (and costume) etc…
Wu Kong is maxed which is awesome!
You’ve spent some mats on Onatel so finish her to 3-70
Then work on the 4* heroes. Jackal first then Li Xiu & Costume then Chao.
Then come back round and finish Onatel. Then back to 4* heroes
Ursena is a great 5* hero… Probably don’t need Boss-Wolf as he’s mainly a tank hero (who Ursena can quite capably be too.)
But you’ve spent some Trap Tools on Boss so finish him to 3-70. then onto 4* heroes
in the 4* region, I would suggest Proteus as the first priority. Hes a gun in events and map stages!
Next I would probably Suggest Cheshire Cat (for defence down against holy titans) and then proabbly a second proteus & Rigard.
With Boss Wolf, I probably wouldn’t max him unless you got 11 tabards sitting around & no other option there.
Hope that helps