Yo there my friend @FishDreams thanks for the tag.
Great advices indeed.
Nothing to add about line those up.
But in my honest opinion … Kash is a better tank than BT.
Kash is a Def hero as Fish said
BT is def/atc hero .
Wu Kong is all use hero and every day hero not just in Titans. I am using him all over E&P I’m even leveling 2nd Wu!
We can’t talk about Wu with out calling Mr. @SandMan the Wu Kong expert .
Back on topic.
My advice is to know exactly what play style you will follow.
If you are F2P/C2P and you are just starting, then you should try to make a solid 3☆ team with at least 2 heroes of each color to be able to beat the stages to earn the Ascending Materials (AM) that you will need to build up your 4☆ heroes who will help you to beat stronger events with 4☆ AM to build up your 5☆ heroes.
So leveling Belith abd Barden are the way before leveling 4☆ greens.
If you are P2P/P2W then you don’t need at all a 3☆ team and you can just pay and get very fine 4☆ heroes, build up a solid rainbow 4☆ 2 teams then start building up your 5☆ heroes.
As I know many of top players of P2P/P2W don’t have any 3☆ heroes at all.
Do ask your self what do you really want to be, how do you will play E&P then chose a way and follow the advices of @FishDreams .
Have a great day