Before selecting a controller type, be sure you understand approximately how to talk to each of those 26 I/O devices. The video camera and communications link could be complex. Depending on those details, a $10 microcontroller could be fine, or it could be hopelessly inadequate.
If you make a terrible mistake such as "oh-no, this interface needs to run 50 times faster!", then you will probably have a better chance of rescuing the project if you used an FPGA instead of a microcontroller. Another technique is to select an FPGA that's big enough for the job, but has a bigger-brother available in the same package footprint, just in case you need it!