Donations must be spent in the way the donor wants. However, if the donation is more than what the beneficiary requires and if postponing their spending leads to wasting the donation, it is permissible to spend them in other ceremonies of Imam Hussein (peace be upon him).

It is permissible as long as it does not comprise of another act which prohibited.

The said act is permissible, but one should not annoy others as this may harm the reputation of the acts of commemorating the Ahlulbait (peace be upon them).

Beating the chests in the ceremonies of Muharram is one of the examples of expressing the sadness and grief to what happened to the Ahlulbait (peace be upon them) in the tragedy of Karbala.

Serving food in Muharram is permissible, but one should refrain from overspending to the level that it becomes prohibited. It is better to have such gatherings with sadness and grief that are appropriate for commemorating Ashura, so it may correspond to the emphasis of the Imams of the Ahlulbait (peace be upon them) on expressing such feeling on these days.

It is important to notice the following issues in answering this question:
First: Those who dislike the followers of the Ahlulbait do not care whether the Shia wear black clothes, but what bothers them is that believers mourn the oppression that took place against the Ahlulbait. By this, they ignore the orders of Almighty Allah and antagonize the Prophet (peace be upon him) intentionally or unintentionally, since Almighty Allah considered the love for the Ahlulbait as the reward for the Prophet’s efforts in guiding mankind when He said: “I ask of you no recompense for this, but to love my kinsfolk.” (42:23) and the Prophet (peace be upon him) ordered us to love his household, and he is the one who cried and mourned for what will happen to his Ahlulbait after Almighty Allah informed him about what is going to happen to them.
Therefore the objection is not against the wearing of black. Rather, their objection is against the sorrow and grief that we have for the Prophet and his household (peace be upon them all). Lots of people wear black clothes and nobody object to such a phenomena.
Second: Some narrations express dislike towards wearing black clothes in itself, but not for the sake of mourning. Other narrations state also that it wearing black was a symbol of Abbasids, and the dislike of wearing black could be for this reason. In a narration, Imam Ja’far Al-Sadiq (peace be upon him) stated after he wore the black clothes when he was called to meet the Abbasid caliph – as it was obligatory at that time to wear black clothes in the presence of the caliph: “I wear it although I know it is the dress of the people of Hellfire,” in reference to the Abbasids. After the end of the Abbasid state, this attribution ended.
Third: Even if it is disliked to wear black clothes, even if it is not the symbol of the Abbasids, there is no doubt that it is recommended to wear black clothes if it was to express the grief in the mourning for the Prophet and his household (peace be upon them) since this a form of commemorating them and expressing grief for them and for the tragedy that took place. Doing do has great benefits for us and it strengthens the faith in the hearts of believers, whether this is achieved by wearing black clothing, or hanging black cloth in public areas, and the like.

Many narrations exhort and urge the believers to cry and express grief and sadness on the day of Ashura for what happened to Imam Hussain (peace be upon him) on that day.
It is also narrated that it is recommended during the day to refrain from dealing with livelihood issues, and from eating and drinking without the intention to fast, and then eat and drink in the late afternoon even by a sip of water.

It is permissible as long as it is not considered to be a propagation of another religion.

The Azadari should take place within the health guidelines in such a way that believers are not harmed from spreading the epidemic.

The exchange of 'salam' does not contradict with sadness and grief.

Thank you for contacting us and we emphasize our interest in submitting what can be to serve the truth and reality. We want to draw your attention to an important issue in your journey to seek the truth and pick the right path which is that you should search for the evidences that each side claims to prove the correctness of its views. So, you should search for what the Shia give as proof of the obligation of following the Ahlulbait after the death of the Holy Prophet (peace be upon him and his progeny) and do not look for the details at the present stage. Once the arguments are proven to you and you choose to follow the Ahlulbait, then you can look for explanations of their practices. If you are convinced, you can practice them, otherwise you can refuse to practice them. If you were to start searching for the explanations for the details of the practices then this might confuse you more.
The thing that the Imams of the Ahlulbait emphasized on is the mourning and expressing pain and passion because of the oppression that the Ahlubait were subjected to, and the tragedies and hardships they faced. The course of practice that believers choose to express the mentioned obligation is entirely personal. Some express their feelings towards Imam Hussein (peace be upon him) and his companions and his household by crying, expressing their sadness and wearing black clothes. Others do so by slapping their chests. Some others self-flagellate to the extent of bleeding as a way to express their grief and sorrow, mourning for the Imam and his family and companions as they were killed and stabbed with spears, swords and arrows.