Hi Malcolm,
As far as I can see they are two, of each other, completely independent peripherals, see note 1 and 2 on page 208. You should have no problem setting one up for I²C and the other for SPI. Lots of registers to set up though ;-)

Make sure to read thru the errata sheet as well, I don't see the MSSP modules being mentioned but apparently there can be some pretty serious silicon bugs. The HLVD module for example appears to be completely useless.

/Henrik.