Thanks. It occurred to me that I should have pointed out that my analysis was for the AX027 part vs. SX027. If anyone has heard of someone designing a board that can accommodate either SX or GX parts, I'd be interested in their experience.
Also, if anyone is interested, here are the pins that are different:
AX027
SX027
PIN
GND
VCCIO_HPS
H13
GND
VCCIOREF_HPS
J13
GND
VCCL_HPS
K14
GND
VCCL_HPS
L13
GND
VCCL_HPS
L14
GND
VCCL_HPS
M13
GND
VCCPLL_HPS
J14
NC
GPIO2_IO0,NAND_ADQ0,SDMMC_DATA0,QSPI_CLK
F12
NC
GPIO2_IO1,NAND_ADQ1,SDMMC_CMD,QSPI_IO0
G16
NC
GPIO2_IO10,NAND_ADQ4,UART1_CTS_N,SDMMC_DATA6,SPIM0_SS0_N,EMAC2_MDIO,I2C_EMAC2_SDA
E12
NC
GPIO2_IO11,NAND_ADQ5,UART1_RX,SDMMC_DATA7,SPIS0_CLK,EMAC2_MDC,I2C_EMAC2_SCL
G15
NC
GPIO2_IO12,NAND_ADQ6,UART1_TX,QSPI_SS2,SPIS0_MOSI,EMAC0_MDIO,I2C_EMAC0_SDA
K15
NC
GPIO2_IO13,NAND_ADQ7,UART1_RX,QSPI_SS3,SPIS0_SS0_N,EMAC0_MDC,I2C_EMAC0_SCL
F13
NC
GPIO2_IO2,NAND_WE_N,SDMMC_CCLK,QSPI_SS0,BOOTSEL2
D12
NC
GPIO2_IO3,NAND_RE_N,SDMMC_DATA1,QSPI_IO1
J12
NC
GPIO2_IO4,NAND_ADQ2,SDMMC_DATA2,QSPI_IO2_WPN
H12
NC
GPIO2_IO5,NAND_ADQ3,SDMMC_DATA3,QSPI_IO3_HOLD
F14
NC
GPIO2_IO6,NAND_CLE,SDMMC_PWR_ENA,SPIM0_SS1_N,SPIS0_MISO,BOOTSEL1
G13
NC
GPIO2_IO7,NAND_ALE,QSPI_SS1,SPIM0_CLK,BOOTSEL0
J15
NC
GPIO2_IO8,NAND_RB,UART1_TX,SDMMC_DATA4,SPIM0_MOSI,EMAC1_MDIO,I2C_EMAC1_SDA
H15
NC
GPIO2_IO9,NAND_CE_N,UART1_RTS_N,SDMMC_DATA5,SPIM0_MISO,EMAC1_MDC,I2C_EMAC1_SCL
F16
NC
HPS_CLK1
G14
NC
HPS_nPOR
K11
NC
HPS_nRST
K12