I don’t know
"Tear in his voice" is an example of a literary device called personification, where human qualities are attributed to non-human things. In this case, the voice is given the human quality of shedding tears.
It's a thing called Juxtaposition, which is where two contrasting things are placed next to each other in a sentence. 'Tears' and 'joy' have connotations of two different emotions.
allusion
The tears ran down Georgie's face.
Metaphor... A+LS FTW
Yes, it has a subject ('they'), a verb ('were') and a complement ('tears of sadness not joy').
Tears can be either a plural noun or a present tense verb.
The rounded black obsidian nodules called Apache Tears are found in Arizona, USA. After years of protests and court challenges, they are now to be called Native American Tears.
She sang with a soulful voice that brought tears to the audience's eyes.
salt
salt
Her tears were unrestrained when she heard that her father had passed on.