The crew take their temperatures in Fahrenheit. Most countries, except the US use Celsius, the US scientific community also uses Celsius as does the ISS crew. Therefore it is reasonable to expect that the international crew in Away should be taking their temperatures in Celsius.
They're three months into their journey, yet communication with Earth happens instantaneously. There should be at least several seconds of delay.
The crew hesitates to treat the injured crew member for fear of contamination via blood. In fact, Mononucleosis is far less contagious than many other diseases and is most often transmitted via saliva. While it can be transmitted via blood, the other person would need to have an open wound for this to take place. Since they all had proper personal protective equipment and no open wounds, there would be no chance of transmitting the virus via the blood.