I try to upgrade level 3 to level 4 but when I choose a sacrifice, it says "cannot complete this action" Level 3 character is fully ascended. Do the sacrifices need to be ascended as well. BTW sacrificial characters are NOT locked

Can you post a screen capture of the message ? I don't think it's the proper message . If anything my guess is you're trying to rank up a level 3 that is not Level 30 . 

no all rarities stay the same level eg uncommon stays uncommon even at level 60 and so on 

only way to get a lego champ is the have the rng gods in your court and pull one :)

I cant rank up my shaman, whenver Im trying to rank her up theres something Error popping up. I ady got complete food for her 

Please post a screen capture of the error message. 

I have Kael at rank 5 at max. I try to upgrade him to level 6 with 5 star 5 champions and it will not let me. I dont understand what is wrong. My Kael is level 50 maxed and is 5 star. The 5 champions I am trying to use are all 5 stars and it wont accept them. What am I missing ?

They're aware of this bug and are working on it.