Factors that break wudhu

Making wudhu after eating food cooked on a fire

Q: There is this book called "The Tablespread Of the Holy Prophet" written by Muhammad Faisal

There is a section on cheese. This hadith is a Sahih Muslim Hadith 687, Narrated by Abu Hurayrah (radhiyallahu anhu).

"Performing ablution in the mosque, he said: I am performing ablution because of having eaten pieces of cheese, for I heard the Messenger of Allah Ta'ala say: Perform ablution (after eating anything) touched by fire."

I would like to know what is meant by "touched by fire" and why should we make wudhu after eating something that is touched by fire?

Ruling of wudhu due to vaginal discharge

Q:

1. May I know all the different types of vaginal discharges and their wudhu/ghusul/najasah ruling according to shariah? Cervical mucus is a normal part of every girl’s monthly cycle and most days in the month she will normally have cervical mucus. This cervical mucus is of varying thickness, opaqueness and stretchability depending on how close or far she is from ovulation. Is this normal cervical mucus discharge what is called “mazi”?

2. I would like to know if wudhu remains or not if the cervical mucus does not exit the private part — it stays within the lips and you can also feel that there is some slippery/wet cervical mucus INSIDE the lips, but it has not exited the lips yet.

3. I was told that wudhu does not break if the fluid does not exit the lips. However, I was reading behishti zewar (وضوء توڑنے والی چیزوں کا بیان) and here is what it says:

مسئلہ ۳۶: پیشاب یا مذی کا قطرہ سوراخ سے باہر نکل آیا لیکن ابھی اس کھال کے اندر ہے جو اوپر ہوتی ہے تب بھی وضوء ٹوٹ گیا۔

What does this mean? I am still confused about if mazi is the normal cervical fluid.

4. I do not know what a wet dream is.

Repeating salaah if one found out that wudhu was not valid

Q: I was sitting after performing salaah when I noticed that there is a black, sticky substance on my foot through which water could not pass. It was the size of a whole round fingernail, and I had not seen it before.

Then, my brother told me that he saw it since 3 or 4 days on my foot. I had also led jamaat during these days. Will I have to repeat all the salaah that I had offered on these days? Will those who followed me in jamaat also have to repeat their salaah?