I would not want to split IO groups. For instance, 4 analogs on one controller and 4 on another.
Why is this? What if they are in different rooms or even buildings?
8- scaleable analog inputs (I can get by on 4 for this particular project)
4 - scaleable analog outputs (I can get by on 2 for this particular project)
16 - Digital inputs (I can get by on 12 for this particular project)
8 - Digital outputs (Technically I only need 4 if I can use a serial display for textual alarm display)
Serial Display
Is this all one one board?
32 bit analog data
Yikes, above my pay grade 
Can you give us some idea of the topology, so far it seems there's just a single board with comms to a PC or whatever, but that's a very limiting arrangement.
Rob