What are your target values?
You have two numbers in, and you control one pump. Should the pump come on when either value exceeds a target? When both values exceed a target? When some function of the two values exceeds a target?
What kind of hysteresis would be suitable? You don't want the pump rapidly switching on and off when the temperature and humidity are very close to the target. Should it be based on the values, or did you want something time-based?
Did you want the values to be adjustable?
Did you want some sort of override switch, so that the pump could be manually turned on or off? Did you want any sort of indicator LEDs?
Are you able to edit the values in a sketch yourself, to tune them to what you need? Are you comfortable with compiling a sketch and uploading it onto an arduino? Do you realise that what you will get is some code that you need to compile and upload? Or where you expecting that someone would supply you with a board with the sketch loaded onto it?
Your MLX90614 uses SMBus, which is mostly compatible with I2C, and your Hr202 is an analog input.
Your coder will almost certainly need to work with an actual MLX90614 to be sure the code is talking to it correctly. So he or she will need to source one of these things, which will take a little time and a few bucks. Is this ok? If you need this job done in a very tight time frame, then it might not be do-able.
The humidity sensor is trickier - it will need a voltage divider circuit (same as using a potentiometer). Do you already know what voltage divider values you will be using, and the target numbers on the analog input? Or will your coder need to work it out from the data sheet?
(EDIT) The data sheet is here: http://www.elecrow.com/download/HR202%20Humidity%20Sensor.pdf . The resistance of the humidity sensor is dependent on both the relative humidity and the temperature. Determining how to convert the value off it into the decision you want the code to make is not trivial.
Is operating your motor simply a matter (from a programming point of view) of setting a digital output to HIGH or LOW? It looks like it is - I assume you are using some sort of motor shield. Bit it doesn't hurt to ask.
When did you want this by?
And, of course, what's it worth to you?