Taking a loan from someone who took a loan on interest

Q:

1. If I borrow a certain amount of money from a person with the intention of paying back the exact amount to my lender but the money that has been lended to me is money that has been borrowed by my lender that has agreed to pay back with riba to his lender. Can I use the money knowing this?

2. If I lend a person money but the person pays back my money from borrowing from another person with riba? Can I accept?

3. If a person gives me a gift but I doubt if the gift is bought from haraam money. Can I take it?

4. I lend someone $180 but they pay back me $200 without me asking can I keep?

Finding wadi on one's ihraam and clothing during hajj

Q: When I was performing Hajj, in mina, muzdalifah and throughout that day where you stone shayateens etc... I noticed that before and after urination wadi has come out of my private part. I am also sure that wadi touches the ihraam which means that my ihraam may also be not clean during that time. I am worried that my hajj may not have been accepted or may be I have to pay for damm (hajj penalty)?

Zawaal time

Q: I reside in an area and noticed that both mussallees and trustees of the local masjid are unmindful of zawaal, this is mainly on a Juma as we come early for jumah.

I find that people are performing nafl salaah during this time including the trustees and Ulema. The other masjids that I attend during this time either put on a light or a sign that say zawal.

I would like to know the following:

Firstly when is zawaal and how long does it last for? Example the times I see on the calendar for today as well as salaah times from crescent mobile says zawal 11:59am.

Does this mean zawal sets in at this time or ends at this time?

During this time of zawal what should be done and what should not be done?

Should I bring this to the attention of the trustees and will I be accountable For this if I don't?

This has been going on for the past 3 years or so. I dont want people to be offended and neither do I want to commit any wrong actions, thus when attending this masjid I look at zawal time on my phone and as a precaution I commence my nafl salaah 10 mins after the stipulated zawal time.