How should I deal with the whispers of the devil with regard to ablution and purity?
Whispers in ablution are from the devil, and so you should take refuge in Allah from the devil`s evil suggestions that aim to distort the religion. Thus, once an organ is completely pure, don`t question its purity since having whispers doesn`t mean that the purity is invalid as it has already been established.
Does tooth extraction during the day in Ramadan break the fast?
Simply extracting a tooth during the day in Ramadan does not break the fast. However, if water or blood enters the body cavity, the fast becomes invalid.
Whoever's fast is invalidated in this way must refrain from eating and drinking for the rest of the day out of respect for the sacred month and make up for that day later.
It is preferable to postpone the extraction until nighttime or after Ramadan if possible.
Can someone who begins a voluntary fast break it?
It is preferable for someone who begins an act of worship not to break it.
Allah the Exalted has said {what means}: "and let not your [good] deeds come to nought!" [Muhammad/33].
However, if a person starts a voluntary fast (nafl) and needs to break it, they are going against what is preferable, but there is no sin upon them.
What is the ruling of Islamic Law on eating or drinking forgetfully while observing the kaffarah fasting?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
If someone eats or drinks out of forgetfulness while fasting, it is simply that Allah has fed them and given them drink. Their fast is not broken by this; rather, they should continue fasting. This ruling applies whether the fast is an obligatory one (like Ramadan), a make-up fast (Qada), an expiation (Kaffarah), or a voluntary (Nafal) fast. And Allah the Exalted knows best.