Woman seeing yellow discharge before and after the days of haidh

Q:

1. I learnt that a female's yellow discharge is regarded as haidh during the day's of haidh and istihaadha out of it. Therefore, if one experiences this discharge before the fifteen days tuhr is up, sometimes just a few days before haidh begins and sometimes through the tuhr period, does one need to treat it as normal istihaadha, i.e. change and make a fresh wudhu for every salah, or as normal discharge, i.e wudhu only breaks when the discharge comes out?

2. Regarding the yellow discharge, if the lady gets it after 11 days of tuhr and it continues till the 16th day, and thereafter she gets her normal haidh (proper bleeding that usually lasts for about 8 days and if counted with the yellow discharge would go over 10 days), but her habit is normally 18 days of tuhr, does she count her haidh from the 15th, 16th, or 18th day?

Salaah becoming qadha due to not making fardh ghusl after becoming baaligh

Q: If a male becomes baaligh by having wet dream and ghusl becomes fardh on him, but he doesn't know that in Shariat you have to perform ghusl after having a wet dream. So he keeps praying with just making wudhu and after 3-4 months of his puberty, he comes to know that ghusl becomes fardh by wet dream. So are all his prayers in these 3-4 months counted or does he have to make qadha?

While offering these prayers again will he make intention of praying qadha prayer or will he make intention of repeating the prayer (I'adah)?

Sahib-e-Tarteeb making qadha of Zuhr Salaah after performing Asr Salaah

Q: I have a question about the Mas'ala of Sahib-e-Tarteeb:

1. If a person is Sahib-e-Tarteeb and he misses a prayer, for e.g. Zuhr. And then prays Asr and after praying Asr, he prays the Qaza of Zuhr. So obviously his Asr prayer is invalid. But what if after praying his Zuhr Qaza, he misses 6 more prayers. So he no longer remains Sahib-e-Tarteeb. So by missing 6 prayers will that Asr prayer which he offered becomes valid?

2. What if he then again offers all those 6 prayers' Qaza and again becomes Shahib-e-Tarteeb, will now his Asr prayer become invalid again?

Taubah from making gheebat (backbiting)

Q: Sometime ago I backbit and engaged in alot of idle talk about alot of people as I was not much of a practicing Muslim. Those people are not aware of my backbiting. Now I have turned back to Allah; I have repented alot and repented sincerely and realized my mistake.

It turns out that the people I used to backbite are alot since I dont remember them all can I make dua generally for all people that I backbit without taking their names or mentioning them? like "Ya Allah, forgive all the people that I backbit and raise them in ranks".

Also, will Allah Ta'ala forgive me? I am afraid if I tell those people that I backbit them it will cause some hatred in their hearts for me. So i decided not to approach them and repented sincerely.