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. 

Using Bay'as Salam to make a dropshipping business halaal

Q: I would like to know more about Bay'as Salam and how I can use this to make my dropshipping business halaal?

When a customer places an order, the supplier ships the product directly to the customer. You pay the supplier the wholesale cost of the product, and you keep the difference between the wholesale cost and the retail price as your profit. In a Salam contract, the buyer and seller agree on the price, quantity, and delivery date of the product. The seller receives the price of the product in advance, providing them with the necessary funds to produce the product. The buyer then takes delivery of the product at the agreed-upon future date. I would like to know if the above information provided on salam will allow me to use it in the dropshipping context as mentioned in the first paragraph.

Washing limbs more than three times during wudhu and water reaching the skin under the beard

Q: During wuzu, it is sunnat to wash the limbs of our body 3 times be it the face, hands or legs.

1. What if we feel that on 3 times we haven't fully wet the particular limb, can we then wash a particular limb more than 3 times? Will this invalidate the wudu or that just means we will leave the sunnat but wudu will be done?

2. As for cleaning the face during wuzu, is it necessary that water reaches in the gaps and the skin below the beard/moustache?