These are all 5* and 4* Heroes I have.
The question for 5* heroes is
The question for 4* heroes is
Thank you very much for every advice.
I cannot help much with your 5* because I’m too unfamiliar with most of them, but Joon is a for sure good choice to level! That I know.
Now for your 4*.
Dark: Rigard is by far the best 4* healer available, so definitely level him.
Holy: Wukong is essential if you want a good titan team. If you don’t care about the titan, level Hu Tao! This guy wrecks me in raids.
Green: Little John is a solid choice. I always struggle when raiding them.
Red: Colin Has one of the best 4* aoe attacks in the game. BUT Wilbur is an A+ rating red hero. Very powerful too.
Blue: Grimm is great! Not much else to say there.
Edit: Disclaimer, these are my personal preferences based off of who I have trouble in raids against.
Do not feed any of your duplicate 4stars or 5 stars; if a it’s true that a new building will be coming that lets you make use of your duplicates, I’d hang on to the 4 and 5 star duplicates: SGG "Ask Me Anything" AMA transcript - 13 March 2019 - #3 by Kerridoc (scroll down to Q6.)
IMO: work on 4 stars before 5 stars.
Ascend Tiburtus before Cyprian.
Ascend Hu Tao before Chao.
Level and max one of Grimm or Triton (tough choice here, both are great)
Ascend Kashrek (for a better defense team) or Caedmon (for more general purpose utility)
Ascend Scarlett, then work on Wilbur.
level the 4* first:
i’d recommend rigard first. he is a beast!!
then wilbur. those are 2 of the best 4* in the game.
afterwards i’d go with grimm, triton, colen and tiburtus.
once you maxed out an amount of decent 4* you can focus on joon. sartana and leonidas are awesome too.
anyway… you’ll be busy the next months maxing a few heroes 
have fun and let us know how your process does.
I’m no expert, but I have all of these heroes with the exception of 3. I’m a bit of a collector lol! That being said, this is my interpretation of what would be best:)
4* Dark: Rigard is an awesome healer who also cleanses- everyone needs at least one. I kept 3 because he is that good. Finish Tiburtus before Cyprian.
Holy: you already have one maxed wu, and I think that’s enough. But I only use him on Titans so others may disagree. I would finish chao and Hu- then LiXiu. I don’t care for Danzaburo. I always feed him away.
Ice: All of these heroes are great! Grimm, Triton, and Sonya all hit and have additional aspects to their specials that are helpful. Boril is a good tank. I don’t think Valeria gets enough love. She is very fast mana and really shines in wars with field aid. If her special fires (and it will), anytime field aid or a healer fires she will steal health.
Nature: I would finish Caedmon and Kashrek first. The order depends on if you need a tank/healer or a hitter who dispels buffs. Then I would finish Peters.
Fire: finish Scarlett then Wilbur. Sumitomo would be next if it were me.
5*: Dark: finish Kiona (she’s awesome- I have 2 that are used frequently!) then Sartana with Domitia next.
Holy: Joon, Joon, Joon!! I have 3 and he’s fantastic!!
