@brutzler , There is no way to be sure what those probes are but they do not have the correct thermocouple plugs so they are more than likely thermistors. The other possibility is that they are Pt 100 probes. If they were thermistors and you could find the data on them then they would be easier to implement than J or K type thermocouples. I have never used Pt 100 probes. To some extent it depends on the temperature range you want to measure, thermocouples can go to very high temperatures. Thermistors are not linear in their output but a formula (Steinhart-Hart) can be used to linearize them. I think there is an Arduino library for using thermisters.
Thermocouples need cold junction compensation and the correct connecting plugs/cables otherwise parasitic junctions are formed.