Remember that this is something of an unconventional Merfolk deck; very few builds run this many Vehicles. The reason for the higher-end, trigger-on-tapping merfolk is so that you don't have to tap all your army to crew a single
Bomat Bazaar Barge, and so that you can reliably trigger their abilities even on the turn they come in. Most Merfolk decks are supposed to be fast, but this one plays with more of a mid-to-late game in mind, gaining life, generating chump blockers and bouncing permanents to protect itself while it draws more vehicles to crew.
That said, it's still open to change. I'm not 100% if
Triton Shorestalker's aggressive theme fits properly here, but I'm happy to take on similar, cheap merfolk if people think that would help the deck advance its gameplan. Any other ideas? Thanks in advance!