CC2567: it provides up to +10dBm Tx Power, and -93dBm typical sensitivity, according to the datasheet
CC257x:, it provides Tx power range of -21 to +4 dBm, -86dBm receiver typical sensitivity
For additional hardware specific figures not present in the datasheet, we would recommend contacting TI.
Not sure how helpful it would be to know the flash/RAM/stack size of these parts, as they are Network Processors, and thus, none of that would be available for your application.
When using a wireless network processor, you would need a microcontroller for your application, and you can select one with the flash/RAM that best fits your needs. Microcontroller choice depends on your particular application needs. The reference code we make available is for the MSP430, as it is a good match for ultra low power applications, however, it really depends on your application what would be the most suitable choice for you.