it is appropriate to break the rule that requires subjects joined by and to use a plural verb when either and neither are subjects. They always take singular verb.
For example :
Either of us is capable of doing the job
It depends what kind of activist we are talking about. If the activist was for human rights, we could possibly consider them as a humanitarian, because the definition for humanitarian is: concerned with or seeking to promote human welfare. This is quite similar to a human rights activist, so I would say yes.
Something you cant see, hear, taste, or smell
I would say the first one! Good luck!
