When would the souls be reunited with the regenerated human bodies in the graves?

Verses 1-14 of Chapter 81:
When the sun is folded up, and when the stars scatter, and when the mountains are set in motion, and when the ten month pregnant she-camels are left untended, and when the beasts are gathered together, and when the oceans are set ablaze, and when the souls are reunited (with their bodies), and when the infant girl, buried alive, is asked for what crime she was slain, and when the records are unfolded, and when the veil of heaven is removed,and when Hell is set blazing, and when Paradise is brought near, then each person shall know what he has brought with him.

Verses 1-5 of Chapter 82:
When the heaven is cleft asunder, and when the stars scatter, and when the seas are torn apart, and when the graves are laid open. Then every person shall know all his works, the former and the latter.

What will people feel on the Day of Judgement after having been raised up from their respective graves?

People will feel that they have slept for hours only in the graves!

Verses 51-52 of Chapter 36:

And the Trumpet will be blown and behold from the graves they will come out quickly to their Lord. They will say: "Woe to us! Who has raised us up from our place of sleep.'' (It will be said to them): "This is what the Most Gracious had promised, and the Messengers spoke truth!''

Verse 259 of Chapter 2:

Or take the case of the one who passed by a township that had fallen down upon its roofs. He exclaimed, "How shall Allah bring back to life this township that has become dead?" At this Allah caused him to die and he lay dead for a hundred years. Then Allah brought him back to life and asked him, "How long have you lain here?" He answered. "I might have lain here for a day or a few hours." Allah said, "Nay, you have been lying here in this state for a hundred years: now, just have a look at your food and your drink; they have not become spoiled in the least. Then have a look at your ass, (and see that his very bones have become rotten) and We have done this in order to make you a Sign for the people. Look, how We raise up the skeleton and set the bones (of the ass) and cover them with flesh and (put breath of life into them)." And when the Reality became manifest to him, he said, "I know that Allah has power over everything."

Verse 19 of Chapter 18:

And similarly We awakened them so that they may enquire about each other; a speaker among them said, "How long have you stayed here?" Some among them said, "We have stayed a day or part of a day"; the others said, "Your Lord well knows how long you have stayed; therefore send one of you to the city with this silver coin - he may then check which food available there is purer, in order to bring some of it for you to eat - and he must be courteous and not inform anyone about you."

Does God never make the reward of the good doers to be lost in this world?

Verse 56 of Chapter 12:
Thus did We give established power to Joseph in the land, to take possession therein as, when, or where he pleased. We bestow of our Mercy on whom We please, and We suffer not, to be lost, the reward of those who do good.

Does God bestow special favor upon the poor people as well as the true believers?

Verses 79-82 of Chapter 18:
As for the boat, it belonged to poor people working in the sea. So I wished to make a defective damage in it, as there was a king behind them who seized every boat by force. And as for the boy, his parents were believers, and we feared he would oppress them by rebellion and disbelief. So we intended that their Lord should exchange him for them for one better in righteousness and nearer to mercy. And as for the wall, it belonged to two orphan boys in the town; and there was under it a treasure belonging to them; and their father was a righteous man, and your Lord intended that they should attain their age of full strength and take out their treasure as a mercy from your Lord. And I did them not of my own accord. That is the interpretation of those (things) over which you could not be patient.