Why would you consider the 24R if you need 30 inputs? The first sentence of the description is:
"PreSonus StudioLive 24R 26-Input" (I didn't dig into the possibility that the stage box would somehow extend the number of inputs for the 24R).
So - you need the 32R. (unless the cost savings of 24R and the NSB make the hassle of not having 32 native inputs worth it)
Now for the snake. I'm guessing the same math will apply. Channels/Inputs are typically in sets of 8's or at least 2's.
So if you say you need 30, you need 32.
Without budgetary or other factors, it seems pretty clear.