Factors that break and don't break the fast

Q: Is it permissible to wet the miswak before using it while fasting? 

Q: My question is related to the validity of the fast. 

While doing my Kaffarah, I was cleaning my home and dusting off some shelves on the 58th day out of 60 days. Some dust flew in the air and I inhaled it. I looked the issue up in Maraqi al-Falah and it said in the chapter of that which does not invalidate the fast, "dust or smoke alongside smoke from wood or incense entering one’s throat without one’s doing". 

Here, it is mentioned, that smoke and dust which is inhaled by ones own doing will invalidate the fast. Does the aspect of causing it oneself only apply to smoke or does it apply to dust, too? 

Is the scenario I described classed as deliberately causing it myself? Do I have to restart my Kaffarah because of the fast becoming invalide or is the fast still valid?

Q: I had used an inhaler (pump) just before subh saadiq. After subh saadiq, I got a taste of the liquid medication in my mouth. Is my fast valid?

Q: Is it permissible to apply oil to the scalp or body while fasting?

Q: Will the fast break if sperm comes out while urinating?

Q: Would it be permissible for a female who needs to use a disposable catheter to use it while fasting, if she needs to use it due to medical reasons. The catheter is inserted into the bladder, using a lubricating gel.

Q: I have an eye inflammation which requires me to use eye drops five times a day. Will it be permissible to use it while fasting?

Q: Will it invalidate one's fast if saliva is found on the lips and one licks the lips? Does the ruling differ if saliva is found outside the mouth?

Q:

1. If a woman inserts dry tissue into her private parts to prevent discharge from breaking her wudhu, does her fast break?

2. If a woman puts water inside her private parts just at the front to clean discharge which if not cleaned would cause her to become Ma'zoor, does her fast break?

Q: Is it permissible to sit in a room which has a humidifier on whilst fasting if there is only water in the humidifier?