I will give you a Break Down for Clan Boss. 

I believe a successful Clan Boss Team should strive to have the below skills: 

Critical Skills for Clan Boss

1. Decrease Attack  

2. Decrease Defense  

3. Weaken  

4. Poison / HP Burn  

5. Speed Tuning (Team Counter Attack Hero) or Speed Lapping (Team Turn Meter Filling Hero) 

Bonus Skills for Clan Boss

6. Healer  

7. Shielder  

8. Debuff Extender  

9. Increase Defense  

10. Ally Protection 

Your Clan Boss team should strive to have heroes who can do each 1 of these things. 

It isn't going to be easy to get a team of 5 heroes to have all of these things. 

However, the goal would be to get as many as you can. 

You should start with the top 5 skills which are most critical. 

Than you can move downward and pick up other stuff as you can. 

So after looking at my list + comparing it to your heroes which you told me about. 

I have come up with the following Clan Boss team: 

Tayrel ---------------> Decrease Attack -----------------------> #1 Skill

Athel -----------------> Weaken ---------------------------------> #3 Skill

Steelskull -----------> Poison + Increase Defense --------> #4 + #9 Skills   

Apothacury ---------> Speed Lapping + Healing ----------> #5 + #6 Skills

Miscreated M. -----> Shields + Ally Protection ------------> #7 + #10 Skills

This is the team set up I would try out for your Clan Boss Team.

I think it could be a very good set up.

You want to make your team move 2 times before the Clan Boss takes a move. 

Here are what my estimated Clan Boss Speed Amounts are: 

Ultra Nightmare Clan Boss moves at 190 Speed 

Nightmare Clan Boss moves at 170 Speed 

Brutal Clan Boss moves at 150 Speed  

Hard Clan Boss moves at 130 Speed  

Normal Clan Boss moves at 110 Speed  

Easy Clan Boss moves at 90 Speed  

Here are what my estimated Clan Boss Speed Amounts are for Players trying to Speed Tune:

Ultra Nightmare - Your team should move between 191 - 209 Speed  

Nightmare - Your team should move between 171 - 189 Speed  

Brutal - Your team should move between 151 - 169 Speed 

Hard - Your team should move between 131 - 149 Speed  

Normal - Your team should move between 111 - 129 Speed  

Easy - Your team should move between 91 - 109 Speed  

Here are what my estimated Clan Boss Speed Amounts are for Players trying to Speed Lap:

Ultra Nightmare - Your team should move between 211 - 229 Speed   

Nightmare - Your team should move between 191 - 209 Speed   

Brutal - Your team should move between 171 - 189 Speed  

Hard - Your team should move between 151 - 169 Speed   

Normal - Your team should move between 131 - 149 Speed   

Easy - Your team should move between 111 - 129 Speed  

Here are what my estimated Clan Boss Resistance Amounts are:

Ultra Nightmare Clan Boss - 230 

Nightmare Clan Boss - 170 

Brutal Clan Boss - 120 

Hard Clan Boss - 80 

Normal Clan Boss - 50 

Easy Clan Boss - 30 

Here are what my estimated Clan Boss Accuracy Amounts are which you will need:

Ultra Nightmare Clan Boss - 240 

Nightmare Clan Boss - 180 

Brutal Clan Boss - 130 

Hard Clan Boss - 90 

Normal Clan Boss - 60 

Easy Clan Boss - 40

Tayrel, Aothar, Steelskull, Apo, Royal Guard