What are the differences between joy (piti), bliss (sukha) and peace (santi) and how do the qualities relate to Nibbana?

This is a follow-on to [this question](https://buddhism.stackexchange.com/q/34694/254) What's the connection or difference between joy (piti), and the "bliss" (sukha) and peace (santi) of Nibbana? Is one required to seek joy to attain Nibbana? Why? Should one seek sukha, peace, or Nibbana (to attain Nibbana)? If Nibbana and joy are different then why is (or what's meant by saying that) joy is one of the [path factors](https://en.wikipedia.org/wiki/Seven_Factors_of_Awakening) ? It seems to me the meaning of the English words "bliss" or "happiness" is synonymous with "joy" so why does it seem like Nibbana has been described as "bliss" or "happiness"? In my opinion if there is no element of "joy", "pleasure", "delight" etc. to the attainment of Nibbana then it is wrong to refer to it as "happiness" or "bliss". I don't understand how it could be possible for there to be an unconditioned happiness or bliss.