I wouldn't run 4 Shard Volley maindeck, it's just a finisher because you're running few enough lands that you can't afford to blow one up until the end of the game. 2 is the most I would run, or replace them all with Skewer - it's not win-more when literally the entire deck is built to activate Spectacle. (Stage is, to a point, since if you need the impulse draw effect you don't have the cards to turn it on in the first place).

Lavamancer is a card I've tried a few times, and I never really wanted more than 2 in the deck because he's slow and doesn't play nicely in multiples. With Orcish Bowmasters and Fury in the format, I'm not convinced he's playable at all. Sure, cards get in the graveyard pretty quick when fetches are involved so he can go off every turn, but all the other playable 1-mana creatures (like Swiftspear or Soul-Scar Mage) also represent 2 damage a turn.

Don't forget Inspiring Vantage. I would run 3 or 4.

Roast is the better removal spell if you're thinking about Fry, since it answers Sheoldred and Fry won't typically be enough for a Murktide Regent anyway.

Thunderous Wrath shouldn't even be a maybe, you're more likely to mulligan it than to topdeck it.