Sunnats and aadaab of wudhu

Q: I was recently diagnosed with OCD, which results in me having a lot of doubts about things. However, I’ve been working on getting better Alhamdulillah. I just had a quick question regarding what to do in the following ghusl/wudhu scenarios: 

(1) In Wudhu, when I wash my face, water also rolls down my arms and also splashes or falls off my face onto my arms. Then when I go to pour water on my arm, I’m not sure which part of my arm is wet with the fresh water or wet with the water that rolled/splashed off my face onto my arm. What to do in this scenario? 

(2) In Ghusl, I often doubt whether water has reached the skin under my beard. I have a beard wash soap, which I usually rub fully into my beard then wash the soap away while rubbing my beard with my hands. Once the soap has been rubbed and washed away from the beard, can I assume that the skin underneath the beard has also been washed? 

(3) In Wudhu I try to just wash 3 times and move on. However sometimes I forget whether I have washed 2 or 3 times. What do in this scenario?

Q: I am in a state of ritual impurity and water is available, but I am unable to perform ablution due to shyness and lack of time.

Q: I have a pain in my hand and was advised by a physiotherapist to tape it using kinesiology/sports tape. The tape is difficult to remove once its stuck and it falls off on its own after a few days. Will wudhu be valid if I make masah over the tape?

Q: If one’s limb is dry after making wudhu and one is unsure if the whole feet or face was washed and one read salaah with that wudhu, does the salaah need to be repeated?

Q: What is the correct method of gargling the mouth for Shawafi?

Q: In wudhu, if sometimes we wash all the parts one time instead of 3 times, can we offer salah with this wudhu?

Q: If I wash my feet for wudhu by putting my feet in an empty bucket and pouring water on it and then wiping it. I do this 3 times for each foot. In-between the times that I wash my feet, my feet touch the water in the bucket that has dropped off my feet. Is my wudhu valid?

Q: Is it permissible if we wash all parts (limbs) in wudhu one time?

Q: I’ve heard from someone that it is impermissible to reuse water for wudhu, however if someone lets the water from the tap run over his arm such that only one side of the arm is being directly hit with the water and the other side is getting wet by the water flowing over the arm, then will this be a valid wudhu?

Q: What are the virtues of using a mudd when making wudhu or ghusl? Are there etiquettes of using a mudd?