The good news about being unable to complete CE-5 is that it's only about 10% more sanity efficient than CE-4. It's still important, but a lot less important that being able to do LS-5.
Here's the team I beat it with about a month ago (now that things are higher level and I have better units, I need to fix my auto-deploy to make it faster)...
1 Sniper (I used Meteor because I can't stand Kroos' KO KO DAYO spam every 5 seconds. But, Kroos would work just fine if she's all that you have).
1 Full Refund Vanguard (Plume, Vigna, Grani - I used Vigna in my original run because Grani wasn't a thing yet. I need to update the run with Grani).
1 AoE caster for the back-line of THICC boiz (I used 12F for this. Mostly because he's the only other AOE caster besides Lava that I had. Others would probably work fine, but CP might be an issue).
2 healers and Lancet-2 (never underestimate Lancet-2. Fucking awesome unit that ignore deployment limits).
2 ST Casters (I used Amiya and Orchid for this. Orchid is technically a slower/supporter, but she was the only other arts damage dealer I had at the time. Did I mention I need to update the run?).
1 THICC guard (I used Melantha because she's cheap, all I had for "tanky" guards, and she's a relatively low cost. Any survival style guard should work fine here though - Spectre, Skadi, etc.).
1 defender (Cuora because duh)
1 CP generating vanguard (I used Zima, but Courier, Texas, etc. would work fine).
1 AoE caster for dealing with late-round frontline
If you bros need help with positioning and such still, let me know and I'll go over my strat/auto-deploy.