Suggestions:

Bubblesmith -> Aperion Guard: I think this is such an easy oppurtunity to perfectly add to the lore. Vanar protect the great tree aperion, the minion has a protective effect, voila, Aperion guards are Vanar specialized in defensive magic.

Elderchain Cultist -> Soulsword Spectre: This is less direct, but it references the sprite and the fact that it look a bit like a weaker spectral revenant (black smoke/fur on the back, wearing a mask, similar armor). It's one lore connection more between minions!

Echo Mage -> Radient Echoist: While echo mage is not too bad, the name can be improved by the sprite reference "radient" and the introduction of the notion echoist, implying that within the Lyonar faction there exists a class of arcanysts that specialize in spell duplication. As this is a legendary card, it may also be a particulary powerful echoist, earning the title "radient"

Rythmweaver -> Pain Oni: Pain references the effect and Oni references the sprite wearing a mask, which resembles that of japanese demons

Bad Omen -> Ghuling/Darkling: Undecided here, but the common idea is that it forges a link to wraithlings, other small 0 cost abyssian creatures.

Soul-Scythe -> Nightsorrow Reaper/Harvester: Establishing the dual dagger wielding Nightsorrow school. The reapers/harvesters of this school specialize in gathering souls to summon other creatures

Timecloak Coiler -> Ember Highlander: Referencing the Ember Highlands of Magaari. Just imagine these majestic creatures walking over the fantastic landscape seen in one of the main menu backgrounds

Mementos -> Icebound Petals: Some of the petals of the great tree aperion were enclosed in ice after they fell to the ground. This led to magic-imbued but unstable ice formations.

Thanks <3