Max frequency and data rate of bf70x MSI interface?

I am calculating bandwidth budget for a bf70x design using an eMMC OR a SD card...

What is the absolute max frequency for the MSI interface?

From the HW ref: set MSI_UHS_EXT to 1 = no divider and MSI_CLKDIV to 0 = bypass, the result would be 100MHz.

The data sheet says 50MHz max for MSI clock output. Is that non negotiable for all I/O voltages?

If so, does it matter which of the dividers is used to divide 100MHz->50MHz

Am I correct in assuming there is no support for DDR mode?