I just committed a schematic of my proposed circuit to the linked GitHub. The current design is 8 sensors, that consist of a simple voltage divider, powered by a PWM control from the micro, fed into an op-amp, through a low pass filter out the the 8 analog inputs on the micro. Included with the KiCad files, there is a PDF of the current schematic as well as an excel file that I was using for my component calculations. You may notice on the schematic that there are not a lot of values specified. This is mostly because the circuit works with lots of combinations of values, thus the worksheet. Next up is the layout.

As an aside, I'm happy to see that I have 6 followers on this project, a good incentive to make it work. Thank you! I'm not a trained EE, so I welcome any advice, though I may limit my design decisions to the ones I understand, at least at first.