In reference to the later point. Dispel magic has been confirmed to not be intended to work on non spell but yet magical effects. The difference seems to be whether they are cast/replicate an existing spell or not.
the twitter examples of can/can't be dispelled
Arcane ward and magical items can't http://www.sageadvice.eu/2015/11/25/does-dispell-magic-effect-an-arcane-ward/
Channel divinity can't http://www.sageadvice.eu/2015/10/12/does-dispel-magic-auto-work-vs-channel-divinity-powers/
Shadow monk silence can http://www.sageadvice.eu/2015/10/01/can-monk-shadow-arts-silence-be-dispelled/
Spell Effects from potion/item can but the items themselves can't http://www.sageadvice.eu/2015/03/24/dispel-magic-potions/
Huh, interesting! I wonder why it says "magical effect" in the spell description, then, if it's not supposed to be able to dispel magical effects.
I also thought there was some example previously given of it being used to dispel magical effects that weren't spells, like petrification or something, but I may be confused now.