Would this mean, 'what will your answer be' or 'what question will you be answering?'
Technically it can mean both. In German: "Was werden Sie antworten?" in the meaning 'what will your answer be?' and for 'what question will you answer (to)?' we would use "Was werden Sie beantworten?" The little prefix "be" makes all the difference.
Does this also mean the same thing as the English sentence "How will you answer?" or would that be written differently in German?
Ok, and how we say: "What will they answer" ?
Was werden sie antworten. Note the non-capitalised sie.
Why not what will you reply? Isn't reply the same as respond?
Either: "Was werden Sie beantworten" - What will you answer, or "Wie werden Sie antworten" - How will you reply. Simply "was" is not good German.