Is it possible to access the SDIO peripheral on any of the modules?
In a word, no. The Wifi chip is unshakeably joined to the STM32’s SDIO peripheral.
The closest you could get would be trying to fake up SDIO using a SPI peripheral.
Out of interest, what SDIO device were you hoping to attach to your imp? Some SDIO-driven chips can be configured to use SPI as an alternative interface.