What is the ruling on using moisturizing creams on the skin during the day in Ramadan?

Using moisturizing creams on the skin does not break the fast because they do not enter the body cavity (jauf). Any absorption that occurs through the skin pores does not count as entering through an open passage.

What is the ruling on praying behind a disliked Imam?

 

What is the ruling on a person in a state of major impurity (junub) walking or eating before performing the ritual bath?

It is from the Sunnah for a Muslim to hasten to perform the ritual bath for major impurity. However, if he delays it, he does not sin provided he does not miss the prayer. It is permissible for the junub to walk, eat, drink, and sleep. It is recommended for him to perform ablution before these actions to reduce the state of impurity, although the best is for him to perform the ritual bath. And Allah the Almighty knows best.

What do you say about someone who stays up all night on Laylat al-Qadr but misses Fajr prayer?

Such a person has deprived themselves of a great reward. Performing obligatory acts is more beloved to Allah than voluntary acts. Fajr prayer is an obligation, and performing it in congregation is equivalent to worshiping for the entire night. So how can someone neglect it while striving for voluntary prayers?!