When looking up the dictionary, the phrase the first thing and the phrase the second thing are frequently used on the dictionary. And when looking transcript about News or explanations about something. The former and the latte are used every now and then when it seems to repeat too many words to add some details or demonstrate stated before. Then is It okay to use the first thing and the former, the second thing and the latter interchangeably in these sentences below?

He had to choose between giving up his job and giving up his principles. He chose the former.
If your answer is the former, then you are in agreement with two-thirds of them, according to a recent poll.
We eat lots of poultry and fish, but we prefer the latter.
If you place one thing above, before, or over another, you think that the first thing is more important than the second (thing) and you show this in your behaviour.