Trimming a tree on the property of an apartment building

Q: I have a question regarding the trimming and cutting of trees. I live in an apartment building which has a few large trees on the property.

Is it advisable to significantly trim a large tree (which will decrease it's size significantly but alleviate the inconvenience caused by the tree to flat owners)?

Is it advisable to significantly trim a large tree (which will decrease it's size significantly in order to decrease maintenance costs associated with looking after the tree)?

Is it advisable to cut down a large tree to make way for additional parking?

Is it advisable to cut down a large tree in order to decrease maintenance costs?

Asking for forgiveness after making gheebah

Q: Gheebah is a very great sin. الغيبة اشد من الزنا.

So lots of people take it lightly and will still end up speaking bad about people and ask that person forgiveness afterwards etc.

When a person speaks bad regarding another person, if it falls under gheebat, the persons good deeds goes to the person he has spoken ill about. Now if he asks that person forgiveness, even if the person forgives him, will he get his good deeds back? Or will it be such that he can now ask Allah for forgiveness as the person has forgiven him, but he'll have to restart his good deeds?

I feel that people don't realize the gravity of the sin of gheebah, and take it very lightly. Please advise. I'm not an aalima so I am afraid if I'm thinking wrongly so I dislike saying anything regarding it incase I am erroneous in this regard.

Meaning of the Hadith "Allah will say to every Muslim, Jew or Christian - that is your rescue from Hell-Fire"

Q: Sahih Muslim 2767a - Abu Musa' (radhiyallahu anhu) reported that Allah's Messenger (sallallahu alaihi wasallam) said:

When it will be the Day of Resurrection Allah would deliver to every Muslim a Jew or a Christian and say: That is your rescue from Hell-Fire.

According to this hadith, a Jew or Christian will be our rescue from hell fire. I know that they will take our place in hell, but why did Allah said they are our rescue from hell? Is that the real wording? Because the non-muslim take this verse literally.