Coldheart is MVP for Spider 20, so she is a decent candidate. But more importantly, looking at who you have at 60, my guess is you are probably not even getting top chest on brutal cb, let alone top nightmare cb chest. I would focus on that first. 

With that in mind, you actually have all of the pieces you need for a good CB team:

Hotatsu - DEF up, ATK down, Leech

Vizier Ovelis - Debuff Extend

Fayne - All debuffs

Rearguard Sargeant - Ally Protect

[Someone] - Stun Cleanse/Block

For that last spot, look around and see if you have a decent epic to fill the role. If you don't, it's not the end of the world - you can make Vizier your lead to take the stun. After a few rounds of debuff extend, your debuffs will probably be good enough that you can afford to have him only go two rounds out of three.

Also to note - you have the makings of an unkillable team with Seeker. You need a few more pieces to really pull it off, go look up some team ideas.

With all that in mind - I would suggest bringing Vizier to 60 next. He'll really help smooth out your CB runs. I used him on my team all the way up until I got Lydia.

I could see Coffin Smasher slotting in that team too, to help keep attack down up at all times, HP burn and the passive helping keep us alive longer. 

No need - Vizier extends all debuffs :)

Thank  you  somuch  for  the  tips.  Would  you  recommend  spending my  books  on  viz  for  his  skills?  Also  im  pretty  new  why  is  clan  boss  progression so  important?

CB progression is so important, because the chest of the highest CB stages have the chance of incredible good loot: sacred shards, void shards, legendary books.

The great thing about Vizier is that he really doesn't need booking at all. If you happen to be swimming in lego books, you could try a few and hope you get lucky - because really the only thing you want to book for him is his A1. But your odds are not great - chances are you'll end up wasting a ton on his A2 and A3, which you actually want to be turning off for CB. Personally, I think I used like two on him and was super lucky in that they both went to his A1, but if I could go back in time, I would probably not have done it.

This is a good team, except can't you have Hotatsu clear the stun? I guess not, with his three turn cooldown on his passive, and he'll be clearing AoE2 first.

Still, I think Coffin Smasher goes in to add an HP burn, and to get his passive that allows you to shave off 5% of damage from the AoEs for your team.

So, I'd go with Hotatsu, Vizier, Fayne, Rearguard and Coffin Smasher. :)

No  healer?

Hotatsu brings Leech, which, when combined with either Warmaster or Giantslayer, is all the healing you need.

Yeah, Hotatsu is super strong. And Leech is excellent in allowing you to gear with your best equipment, regardless of sets, rather than needing lifesteal gear on everyone. :)

You  should  update Skullcrown  because Skullcrown is  a  beast.