question is

1) how and when was the current format of oosool e diin and furoo e diin formed
various ahaadiis and aayaat point out to the same but the current format was not designed by masooms

2) how much right or wrong can it be (not the belief, I mean the order of placement)

3) why is it not biddah if it was comprised later on

4) as Adal is a part of Tauhiid why is it mentioned seperate

5) as Imaamat is a part of Nabuwat why is it mentioned seperate

There are even more things that are essential belief of religion than the ones commonly mentioned. These 5 and 10 usul and furu e deen are just the ones that are commonly known and mentioned which are extracted from our ahadith of the imams (as).