I verified the schematic direction: the live design already uses an ADS1299 breakout/module header, not a bare ADS1299 IC. The breakout is
J6, a 12-pin header with 3V3, GND, SPI, CS, DRDY, START, RESET, PWDN, BIAS/RLD, and reserved/CLK signals.
I was blocked by execution credits before updating the project files, but no schematic replacement was needed based on the live schematic. Remaining work: update the project notes/spec to remove the bare-ADS1299 option, confirm the exact ADS1299 breakout pinout matches
J6, then resolve the current DRC airwires before manufacturing.