Based on J35T3R's comment, I'm streamlining so it focuses on Spellheart Chimera and Flamespeaker Adept: that is, critters that get benefit (and mana value!) from the instants, sorceries, and instants+scrying that will protect and buff them. Thassa gets to stay, but there's not enough devotion to justify Master of Waves, and the Bident of Thassa really doesn't buy me that much upside. The nice thing about flamespeaker is that, between Thassa and all the +scry cards, it's virtually guaranteed to be at least a 4/3 first strike every turn, and often a 6/3, for 3 CMC. And spellheart will get buffed up by the burns, counters and direct buffs, so that when the first one comes down it's probably 4/3 or 5/3 with flying, trample, for 3 CMC. Finally, I think those 2 heroic red cards do work, because the same buffs/scries that boost flamespeaker/spellheart can be targeted at these guys, so everyone shares in the joy.
Bear in mind, I don't actually own most of these cards yet, but I'm working on it!
Dropped:
1x Vaporkin - Doesn't benefit from the instants/sorceries
1x Master of Waves - Not enough double-blue to make devotion feasible
1x Purphoros, God of the Forge - Pairs nice with Akroan Crusader, but not a focus of this deck
2x Bident of Thassa - With all the scry, drawing extra cards is not really necessary.
1x Triton Tactics - I might want to remove another one of these in favor of another Dissolve or something, but we'll see how it runs with 2 in it.
Added:
2x Lightning Strike - Good ol' Incinerate Jr.; burns, buffs the chimera (and with Prescient Chimera, causes a scry)
2x Magma Jet
1x Spellheart Chimera - I guess if I'm building the deck around this and Flamespeaker, they should be 4-ofs.
1x Flamespeaker Adept