If I decide that I don't want a song in my collection anymore and I purchased it in the iTunes store, will it also be removed from my devices via iCloud if I delete it from my iTunes account?
Yes. it will be removed from iCloud.
Instead just deselect the song from your iTunes library so you can keep the track but not have to re download sometime in the future.
Make sure Music is switched on in Settings > Store under Automatic Downloads
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