I’ll write up one of my long essays, but only because you asked 
I’m sorry, I may be repeating what others have already said, but in order for me to make this a proper Randa post with many paragraphs, I must type up what I’d usually do 
First, I gotta say, I may miss something since this isn’t a photo of your roster, but rather a list. So I apologize if this gets a little scrambled, or I miss something blaringly obvious.
If you find yourself having enough heroes for completing all of the necessary in-game activities with mats (ie Titans, seasonal events, challenges, and quests) is when I’d start focusing on your teams for war. If your team isn’t ready to complete all of those, I would focus on building the necessary heroes for that first. Acquiring mats always should come first 
Honestly though, looking at the heroes you have leveled, I would think you’d be able to complete all rare quests, intermediate and advanced, and Titans alright. I know I can complete intermediate and advanced with 60 and 70 heroes, so I’d think you could too. Seasonal events, however, vary and usually require mana controllers and several items. The stronger the heroes, the better.
Now, leveling. I’d still focus on getting two to three 4* maxed first before starting on the 5* since 4* can be used everywhere and are less time and resource consuming. Even if you have the mats to max them, having enough choices stacking for Titans and events, is where having several 4* maxed in each color comes to play. I’d work on the 5* after you have at least two different maxed choices in each color.
Red: Scarlett is maxed (great tile damage), so I’d take Boldtusk there next for that buff and heal (amazing for Titans and events). You don’t have Wilbur, so I’d suggest leveling Gormek for a pulverizer in red. After that, you could start on your 5*, or continue with more 4*. The remaining 4* I’d focus on would be Lancelot for that buff and tile damage. (4*)
Marjana and Mitsuko are both amazing heroes. Marjana is a jack of all trades, so she’ll be very versatile and a great choice for your first red 80 (because ideally you want to go with the more versatile option since they may be your only 80 in that color for awhile). Mitsuko will be a fun hero to play with, but her reflect special will work the same at 70, whereas Marjana needs to max out to be most effective. If you just really love playing with Mitsy, then you could do her, but I’m leaning toward Marj first. Mitsy will be good for defense though, so if that’s where your priorities lie, and to make her less squishy, you could do her. Both are great heroes, so I don’t think you can really go wrong there.
Wow, just realized you also have Zimkitha lol had to go back and add that. Well, Zim’s cleanse and buff are nice at fast mana, but will still work the same at 70. I’m still leaning toward Marj, then Mitsy, then Zim (personally) (5*)
Colen is nice for defensive purposes, but he can wait to max. Kelile I would bring to 60 when you have the off time though, always want choices for war, but ultimately she should be last (Other 4*).
Blue: Kiril is maxed (great choice with banner and heal) so I’d work on maxing Grimm next since he’s the best pulverizer. Sonya would be third to max for that fast dispel (unless you pull Triton, he should come before her). (4*)
Your 5* options in this color aren’t the best, but the one I’d be more inclined to level would be Aegir. He’s a decent (ish) tank, but he’s also a healer, and you always need healers for war. Although, if you do many pulls, or are patient enough to wait- I would. You could take Aegir to 70, but idk if I’d go past that unless you’re sure he fits with your team, or you just never get any better options. Thorne, well he’s last (5*).
Honestly, I don’t value riposte all that much, so I’d skip leveling Boril unless you really love riposte. I’d take leveling Aegir before him honestly, but that’s just me (Other 4*).
Green: Melendor is maxed, so you have a deep healer with dispel, so after that I’d max Caedmon for a fast dispel. If you find yourself needing a solid tank for war or defense, or you need more healers for war, you could do Kashhrek next. Although, if you don’t need any of those things, I’d push him to the back (since being a tank is really all he’s good at). Since you need a buff in green, I’d do Gadeirus for blue Titans. Little John for the high attack stat, for solid tile damage in green. If you pull Buddy, put him at the top of the list (4*).
Evelyn is obviously amazing, and her dispel will still be helpful, but for her to shine she really needs some offensive greens to play with. I’d put maxing her in the works after you get Caedmon done, maybe even LJ or Gade, depending on how patient you are. She should go to 60/70 so you can still use her for blue Titans, but I’d get working on a few more green 4* before going through all of the trouble of maxing her. Elkanen, well he should be next to last, right before Skittles lol (5*).
Yellow: Wu Kong is maxed, good. Since I don’t see many mana controllers in your roster, I’d actually max Gretel first (unless you get Merlin up there) because mana controlling is crucial for completing a lot of challenges and quests. If you get one leveled before you need to start on her, then I’d do Jackal first for purple Titans and tanks. He really needs other offensive yellows to play with though, so I’d maybe still put him behind Gretel if need be. After that, you could do either Li Xiu or Chao - one is better for defense and controls all mana, the other is better for events, is faster, and controls one person’s mana. I’d do one, then the other. Danza you could do next if you can handle the unpredictability, but idk about him. Hu Tao should be last (4*).
Purple: I’d max Rigard when you get the chance; cleansing is a necessary tool you need in your roster. Plus, he has a nice deep immediate heal. After that, definitely Merlin- his mana control is one of my favorites and he’s super fun to play with. Then, I’d get Tibs up for a pulverizer in purple, always need defense down in every color for Titans and their respective tanks. After that, Sabina because always need more healers. Leave Cyprian til last. If you pull Proteus, move him to the top of the list (4*).
Khiona is an amazing hero, and her buff is incredible. She’ll be mostly used for Titans, but a great hero to ascend once you get the chance. Although, if you pull Kageburado (in Atlantis) or Sartana, I’d maybe put them ahead of her, but she comes before any of the other regular purple 5* (imo). Even though her buff works best paired with Wilbur and Mok-Arr, you’ll still find plenty of use for her as is (5*).
Hopefully that wasn’t too confusing, or too many words. & Hopefully I didn’t repeat too much of what’s already been said; I’ll be honest, I didn’t read everything before typing this up. Honestly, I’d keep with leveling the first few 4* I’ve listed first, then work on the 5*. Hope this helps, good luck!
