Jeeez', if I am right every of your mentioned champs is worth leveling up to lvl 60, though I do not know Abbess and Alure. How far are you at the different game modes? Where do you have a lack of performance? 

Bellower is best at campaign farming and good for Spider Den and everywhere else where aoe dmg is necessary. Skullcrusher is a fancy counterattacker which is good in any situation (esp. at Fire Knight, clanboss, arena), Tayrel has attack break on atk1 which is good at clanboss, Apo and Steelskull are good supporters and are dealing some dmg at the clanboss. Shirimani is as far as I know one of the best legos in arena.

If you do not have a counterattacker I would suggest to lvl up Skullcrusher, because he can increase your dmg at the clanboss dramatically. It all depends on your team you are already using and what you are aiming for. Probably all mentioned champs are very good for building a separate team, but that is beyond my experience/knowledge.

I really need help on witch hero to 6 star next and also whom of them all to spend time and books on 

Skullcrusher, Apothacary, Abbess, Shirimani, Tayrel, Steelskull, Doompriest, Alure and/or Bellowere

I feel the same way...can’t wrap my head around what I need and witch of them all, to give the small amount of free time i have. 

I have a 6 star Kael, so do I spend more time with him and give a Support or Defense hero some like Skullcrusher, Apo or Shirimani 

 Or do I give Tayrel the new post of Attacker and deal with the last mentions later? To awnser Valdys at the same time. 

I’m at lvl 9 in all dungeons except spider...only 5 haven’t given it time. Started Brutal on Campain, I want to 3 star every lvl, and not just run through it.. maby stupid.. 

Im lvl Silver 1 in Arena.... so not that good at any of it. 

Thanx for taking the time to give me some help