Christianity

If you know that he was an innocent person and never against Allah, you can pray for him to get mercy from Allah Who is The Most Merciful.

Wassalam.

You can attend your mother's funeral but with out taking part in any un Islamic worship.

Wassalam.

Yes, you should remove it to avoid bee misunderstood by people who might think that you are a Christian or a supporter. The Christian drawings depicting Jesus are not true and should not claim something which is not true. 

Wassalam.

You need first to understand your own religion and study its principles and foundations before delving in other religions. You must study properly under an able scholar and be sure and firm about your faith, then delve in other religions. This is to protect you from misleading propaganda of others.

Wassalam.

Ignatian discernment has been defined by many Christians as the weighing of facts and feelings about the several good choices which ultimately leads to a choice about what is the best fit for an individual. According to this definition, we don't object on it if the way of thinking and weighing facts is perfect. We as Muslims submit to the will of Allah and abide to it totally without any argument. This is based on the fact that Allah the Exalted  Creator Has the Absolute Knowledge, while human knowledge is always incomplete. That's why we submit to the will of Allah and our thinking and planning and practicing. 

'Wassalam.

Non Muslims don't believe in Quran as The word of Allah, that is why they think away from the facts mentioned in Quran. Allah has clearly stated in Quran the reason of the marriage between the Prophet Muhammad (SAWA) and Zainab Bint Jahsh (And when Zaid has dissolved his marriage with her, We Made her a wife for you, so that the believers should find difficulty in marrying the ex wives of their adopted sons) Sura Al-Ahzaab, verse 37.

'Ahlul Bayt (AS) did mention this marriage being an order from Allah (SWT) to break a wrong common practice against divorcees of the adopted sons.

'It is worth mentioning that this objection on this marriage is not new but it was raised by the enemies of Islam from the Jewish and Nazareth and hypocrites during the life of the Prophet himself (SAWA) and was refuted by Quran, the Prophet and Ahlul Bayt (AS).

It is not strange from the enemies to accuse the Prophet and put false allegations against him.

Wassalam.

If the function is just a social function with out religious acts, then you can attend marriage function of non Muslim, but if the function is a religious function,then Muslim is not permitted to attend any non Islamic religious function.

Wassalam.

If the ads are addressed just for non Muslims who usually use such funeral services, then it is allowed for you to run such ads.

'Wassalam.

Enjoining good and forbidding evil has conditions among which that there should be a reasonable possibility that they might accept. Non Muslims need first to believe in Allah and His messenger Muhammad (SAWA) before we talk to them about performing Prayers and other Islamic life rules.

It is a human responsibility on us to help any human being to know and reach to the Truth, and there is no truth bigger than Allah and His message. We as Muslims should try our best to help others through suitable ways to make their lives better. We always need to be wise and polite.

Wassalam.