Urshifu - Bulk Up Urshifu isn't that good - Choice Band or Focus Sash with U-Turn or Iron Head instead of Bulk Up might be better.
Magnezone - Looks like a good, standard wallbreaker
Rillaboom - Also looks good, you might want to consider Wood Hammer over High Horsepower though, because it hits harder.
Azumarill - Adamant is probably better than Jolly if Aqua Jet is going to be your main attacking move anyways. Also, 4 EVs in HP. It makes Sitrus Berry activate right after Belly Drum.
Zeraora - Your Zeraora is missing a nature. It can work as a mixed attacker, but in this case I think I would recommend making it Jolly with Knock Off instead of Grass Knot. Fire Punch is another option for Ferrothorn, since Close Combat has a 98.8% chance to 2HKO defensive Ferrothorn. If you want to keep Grass Knot for coverage against Ground Types, you should make it Hasty Nature (+ Spe - Def) also you want to use 252 Spe/252 Atk/4 SpA for mixed or 252 Spe/252 Atk/4 Def for a physical set. If you don't go speed nature with 252 Speed EVs, you won't outspeed Dragapult. (which, by the way, Knock Off is good against.)
Kyurem - Again, making it a mixed attacker doesn't look like it's worth it. Roost instead of Freeze-Dry and Jolly Nature would give you better results imo.