I love the music! Super Disney vibes (like Philharmonic/Fantasia mixed with Nightmare Before Christmas). The xylophone was perfect for the image you are crafting, and the high woodwind on top was a great touch. I am worried that one spot sounds a little bit too much like "this is Halloween;" maybe you could take a single beat out of it or modulate a bit? You do not want the listener to accidentally get a song other than yours stuck in their head, haha.
The SFX are fun too! The Heavy Stepping truly sounds like a stomp, but almost as if on marble floors. Perhaps too echoey for your proposed swamp feel? The Unit Lost sound almost sounds like a blaster and would sure scare me as a player if I heard it, so great for indicating a defeated unit! The spellcasting is full of whimsy, makes me think of little fairies, hehe.
Great work on this!!!