It's tempting to think that 50 mL requires Nemeth Code; however, in the Guidance, #5 under Additional Guidelines says (italics added), “Abbreviated measurement units (e.g., ft., min) adjacent to related numbers transcribed in Nemeth Code are part of the technical expression and are transcribed within the Nemeth switch indicators.”
So, any number that is in Nemeth Code (e.g., because it has a decimal, superscript, symbol of currency, etc.) must pull into the Nemeth Code with it a related abbreviation that is next to it, even though that abbreviation would otherwise be transcribed in UEB. But, 50 does not require Nemeth Code, and its abbreviated measurement unit does not either.
As for the degree sign, yes, it does need to be in Nemeth Code.
Happy to help.