Choosing controller/processor when real time feedback control system is required
You first need to define what "real-time" means to you: a reaction with 100 ms (as would be sufficient for your data display-only thing)? 10 ms? 1ms? 100 µs? 10 µs? 1 µs? 

How often do your sensors even give you data?

This will restrict your choice in CPU; but honestly, none of what you describe suggest you need any hard real-time contraints at all so far!

Then, you need to define how much computation needs to happen.

Together, this will define whether you'd want:


one MCU that's both fast enough to calculate all the computation you need and still has enough headroom to still allow for low latency real-time reaction to sensors?
A mixed approach, where a MCU takes care of the real-time low-latency tasks, and highly complex computation is done by an application processor?
Or even something like a digital hardware design on an FPGA to guarantee low reaction times, or to fulfill specific computational tasks that might be hard to do in software.


So, it mainly takes better requirements modelling to start with. From how I read your question, you haven't really written down what your latency requirements are – and what your processor actually needs to do, but you're already choosing components! That's a mistake that we've all done a couple of times, but really, the right approach here is: requirements first, hardware selection later.