What is the ruling on objecting to the Mosque Imam regarding the joining of prayers due to rain?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
It is not permissible for any of the congregants to object to the Imam in the mosque, whether the objection is to demand the joining of prayers or to oppose it; for the general principle is that the Imam possesses the religious knowledge (Al-Ilm al-Shar‘i) that qualifies him to make the decision in this matter. And Allah the Exalted knows best."
Should one who doesn`t perform prayer out of laziness make it up later, and how should he/she do so?
All perfect praise be to Allah,The Lord of The Worlds He/she is obliged to make up missed prayers by offering with each obligatory prayer another one, and if he/she offers two, then it is better. And Allah Knows Best.
Is it permissible to combine and shorten prayers at home before traveling?
It is impermissible to combine and shorten prayers at home before traveling because a person is called a traveler once he/she departs the borders of his/her country, and offering prayer that way was originally intended to exempt a traveler. And Allah Knows Best.
What is the ruling on Friday Ghusl (ritual bath)?
Friday Ghusl is a confirmed Sunna (Prophetic tradition) even if a person wasn`t in a state of Janbah (ritual impurity), or physically unclean. However, one who doesn`t make Ghusl on Friday isn`t sinful for the Prophet (PBUH) said: "It is good for a Muslim to make ablution for Friday prayer, but it is better to make Ghusul. [At-Tirmithi & Abu Dawood].