To help you further a list of sensors that you are considering to measure all of your required attributes would be very helpful. Its hard to help with your project with out that. Additionally, given that your system sounds quite complex and it seems as though you may switch sensor types a few times before your system gets finalized, a T7 would be your best bet. It has the most features and flexibility and is by far the easiest to program.
For measuring 4-20mA sensors, the LJTick-CurrentShunt is highly recommended as you won't have to implement any external circuitry. Each current shunt can measure two 4-20mA sensors.
What pressure transducer are you considering? Some do and some don't. If it requires a stable input voltage somewhere between 0 and 5V you can use the DAC channel on the T7 as your supply voltage.