Aniri in divine shield set, Vogoth in resist, Rector in regen/immo, just to give you ideas of what to shoot for. Obviously rector boosting res, Drex boosting his own res, are huge differences along with Geo's accuracy down and passive damage.
I think you can make something work with perhaps Drex/Doompriest/Ursala (though have to be careful with buffs)/Aniri/Vogoth/Vrask, though admittedly you have quite a few champions I'm not familiar with using, so I could be missing something.
Hopefully one of the more knowledgable folks can chime in and help build on it and we can get you through hard 10. :)
edit: didn't realize how bad i botched geo's accuracy, oops
I have nothing fancy in this game, after a number of failures, I made a list of all my champs and picked the ones with highest resistance. Basically that is in the range of 100 to 150 resistance, laughable, right? This latest group I have shown here seems to win maybe 4/5 times to get the silver bars. The fact that they work out is mostly by chance.
I got up to L20 but cannot get past scarab yet.