Do I need to buffer these sensor outputs in this scenario?
First of all, you're violating minimum load requirement. Minimum load requirement is 80kOhm, so your total resistance at the sensor output has to be below that to ensure stability. With your circuit total resistance in path to ground is 100kOhm, is too much.
Proof: here
Considering that, it looks like you can get away without buffer. Of course, you can always provide minimum load and then buffer it, it will probably be the cleanest way as long as the buffer has low noise and offsets, but I don't think it will change performance by noticable value unless you wanna go megaaccurate. Besides, there is not much info in datasheets regarding output voltage change vs output current. So you can only try it, I'm afraid. Didn't find any minimum load for pressure sensor, so I would probably buffer it and then attach or not attach minimum load resistor before buffer. That way you have a ready circuit where you can simply attach and detach load at your wish. Sensor - Buffer - Voltage divider - MCU. You either put a resistor to ground before buffer or not and see the result. Again, pick op amps carefully. Rail-to-rail, low offset voltage, bias current etc.