Coliseum progression as F2P, stuck at 2/3 characters lvl 50+

What are your scores (%) on each of the 4 bosses? I’ve got 2 units at Lv55 and 1 at Lv54 f2p so you should be able to get more than you have now. 

EDIT:

One thing seems clear, the rewards are structured in such a way to make progression happen at a particular pace, and each tier seems to have a max level for your era units. If you’ve reached that level, you are stuck until you open up a new tier. 

Look at all the level increases that come with an “ability upgrade”, for instance. These seem to always require the materials from the relevant tier that are only awarded in the 40% crate and the 90% crate. All of the other reward tiers award the more standard material needed for all the other level increases - but once you reach a certain point you can’t use those materials anymore. 

When I had Choda at Lv55 and then had to decide between IG90 and STL on who to take to Lv55 next, I picked IG90. I’m now stuck until I clear 90% on t4 of one of the bosses, because the materials I need to improve Choda or IG90 aren’t available until I reach t6 on one or more bosses; and as I described I can’t improve STL until I get a 90% crate. 

I’m still “enjoying” Coliseum, but I’m not terribly keen on having a soft ceiling to how far players can get. I had hoped to clear t5 on one of the bosses before Assaj arrived, but I’m beginning to wonder if this is possible without spending money on materials from the next tier. If I get the 90% crate on the Temple Guards, maybe the ability upgrade for STL will get me over the line, but I doubt I will get that crate.