1mana monsters

Given that every definition of 'gremlin' involves mischief, usually involving difficulties with mechanical devices, I really think we can do better than 'small demon with axe'.  How about: Dizzy target device effect.  There, that's not too overpowered, is it?  Heck, you could probably stat-boost it, too.

As for Skyrian, I think is plenty high enough a cost for its portable Gauntlet effect.  For 3 I think you could get away with a reusable Armbreaker, given that it's mounted on a defenseless 12/12 monster.

And yes, Kelar Citizen is useless, flavorless, and oddly convoluted.  Why?  It's a Citizen.  It's supposed to be productive and relatively useless in combat.  I still think mana generation of some sort is the best way to go, or the 'upgradeable' idea that someone else had.  It could just be as simple as "2 Loses this ability and gains +20/+20, soldier type".