Also we are needing to read and write files on an SD card. This seems to be a capability of FreeRTOS+IO…? Would this be available to the Blackfin or would this require significant porting.
The featured FreeRTOS+IO demo uses the Chan FatFS and lwIP - both of which are third party open source components. You will find links on the featured demo page. Those two components can be integrated into a FreeRTOS application without the need for the FreeRTOS+IO layer, there are several examples available on the web or the FreeRTOS+IO example can be used as a reference.