So lotttssss of text so hopefully I am not missing anything…
Hint for next time, maybe use either screenshots or this tool cause it can show not just “notable” heroes but all levelled ones which give an even better frame of reference.
HeroPlan.io - Tool for tracking your profile's progress, sharing it & to Plan your Hero Use for Class Trials, Challenge Events, Wars, Tavern of Legends Titans AND MORE!)
Red
I would take Marjana to 3-70 then play with her & Elena before making a final decision as to who to ascend to max.
I personally had Elena maxed long before costumes and used her almost every day. I still use her every green titan cause of the colossal attack stat she has & she has a solid place on my red raiding team… for reference I have Marjana at 3-70 & 2-60 with no regrets.
I would avoid doing much with Khagan beyond MAYBE 3-70 until you got nothing better to do with rings that are in excess. Sumitomo is also a pretty meh 4* hero in the end… would level a second Kelile over him personally.
Blue
Agreed to finish Vela.
Next I would probably do a second Sonya as you will quite possibly draw the Sonya costume in a 10x costume summons. Besides, dual dispellers is handy for wars & tournaments.
Then the second Kiril would indeed be warranted…
Agreed that a second boril doesnt have much use EXCEPT in a tournament where you might dual-flank borils on another tank…
Green
I personally would probably do a second LJ over any of your other options…
Kashhrek is a mid-game tank & you’ve kinda gone beyond that point now… He’s not got any real use outside a defence team tank so… 
After that Gobbler would be my next one… odd choice i know but with the coming age of Minion Makers he could be pretty handy… Plus he has a pretty insane attack stat so can deal some hefty tile damage.
Yellow
Personally I would probably take Wu Kong to 4-70 before taking Ranvir up… Main reason being that he’s cheaper to get there.
Ranvir has a use but personally I prefer Wu Kong over Ranvir for several reasons (outlined in the link below).
After Wu I would probably agree to take Vivica to max, especially if you draw her costume. As you said, Leo is a solid 5* sniper… not the best but solid.
Link to a previous analysis of the Titan Damage Boosters & who’s the best:
Purple
Obviously finish off the Sartana you’re working on.
Second sartana to 3-70 is still very useful (mine has been there for a while cause I got some newer shinier heroes)…
Otherwise a second Rigard will be awesome, particularly for wars… I know someone who has like 6 of him maxed… It becomes even better if you draw his costume next month!