Elhain is fine to max in my opinion.  Her usefullness dies off later on, but you gotta play someone those fist 60-90 days and she's ideal unless you get some random fantastic shard pull.

Eating HK was a mistake though.

MM at 60 with Scyl should be able to keep Suzerain, elhain, and someone else alive long enough to do some serious work in dungeons.  Gear makes all the difference, don't underestimate accuracy, and lots of champs benefit massively from 100% crit rate.  Focus on those stats.  Your scyl has enough accuracy for level 10 dungeons, need to get them all above 200 for the level 20 dungeons.

I'm doing the focus on Dragon thing right now, I can consistently clear 15. My suzerain is a bit of a beast. I should have posted his stats instead of Scyl's. Makes me look like slightly less of a nhub. But yeah. I can take Spider to 14. Ice Golem to 16, FK still at 9, can't hit him enough between his turns to drop his shield. All my potion keeps are 15+ fairly easily. I can use Suzerain solo in Minotaur 15. I'm not in a bad place, progression-wise, I'm just not as far as I should be given well over 6 months of daily playtime.

In all honesty, I feel the best use of your energy at the moment is to just build up food. You simply don't have the champs you need to really advance much, and the only place you can reliably build up more is from CB - and unfortunately you don't have a great CB team, so you're kinda in a catch 22.

That's why I recommend you focus on food, and hopefully get shards from other places that you can then use during 2x events.

Other than that - you absolutely should spend all your resources trying to get the Fusion / Fragment champs. That's the most guaranteed way to boost your roster.

I would continue to dragon20 and build 2 armigers (a least 1).  I think with farming dragon for good gear by the time you have 2 armigers you will be able to do all  dungeon 20s.  Won't be fast or sexy, lol.  

F2P will always be lagging against those who put money into the game.  I'm lvl 71 but still only have four Legos on 19 six star champions.  I see people who exceed me in Arena and Clan Boss at much lower levels.  Such is life.