Have some people already been brought to account and admitted to Paradise or Hell?
Question

When does the reckoning begin? Is it when one is lowered into the grave or on the Day of Resurrection? We know that there are some people who have entered Paradise like the hairdresser of Pharaoh’s daughters, and Ja’far ibn Abi Taalib and ‘Abd-Allah ibn Rawaahah, and that there are some people who have entered Hell. But how can that be when we know that the first one to enter Paradise will be the Messenger of Allah (peace and blessings of Allah be upon him)?.
Praise be to Allah.Firstly: 
It is obligatory for every Muslim to believe that the reckoning after death is real, and that reward and punishment will come after the reckoning. Allah says (interpretation of the meaning): 
“So, by your Lord, (O Muhammad ), We shall certainly call all of them to account.
93. For all that they used to do” [al-Hijr 15:92-93] 
“Then surely, We shall question those (people) to whom it (the Book) was sent and verily, We shall question the Messengers” [al-A’raaf 7:6]
Moreover this reckoning will be in two stages: 
The first stage is in the grave, after death: that is when the two angels come and ask him about his Lord, his religion and his Prophet, as is mentioned in the mutawaatir ahaadeeth. This is the trial of the grave from which the Prophet (peace and blessings of Allah be upon him) enjoined us to seek refuge with Allah. 
It was narrated from ‘Aa’ishah (may Allah be pleased with her) that the Prophet (peace and blessings of Allah be upon him) said: “It has been revealed to me that you will be put to trial in the grave.” Narrated by al-Bukhaari (1049) and Muslim (584).  
Ibn Hajar (may Allah have mercy on him) said in Fath al-Baari (1/165): 
The basic meaning of the word fitnah (translated here as trial) is testing and examining. End quote. 
Al-Mannaawi narrated in Fayd al-Qadeer (6/234) that some of the scholars said: 
The believer will be tested in the grave so that it will be easier for him in the place of standing (on the Day of Resurrection), so he will be purified in al-Barzakh so that he may emerge with all issues settled. End quote. 
There may be reward or punishment after this reckoning, so the one who has succeeded will have blessing and happiness in his grave and the one who has lost will have torment and misery. 
All of that happens in the grave or in the life of al-Barzakh. As for Paradise and Hell, no one will enter them fully until after the second stage of the reckoning, which is the reckoning in the Hereafter. 
But some souls may enter Paradise, and taste some of its delights, as an honour from Allah, may He be blessed and exalted.  
The Prophet (peace and blessings of Allah be upon him) said:  
“The soul of the believer is a bird hanging in the trees of Paradise, until Allah restores it to its body on the day when He resurrects him.”
Narrated by Maalik in al-Muwatta’ (1/240); classed as saheeh by Ibn ‘Abd al-Barr in al-Istidhkaar (2/614). 
Hanging in the trees means moving about and eating. 
Ibn al-Qayyim (may Allah have mercy on him) said in his book Haadi al-Arwaah (48): 
This clearly shows that souls may enter Paradise before the Day of Resurrection. End quote. 
Some souls may also be exposed to the Fire and feel some of its heat and torment. 
Allah says (interpretation of the meaning): 
“The Fire, they are exposed to it, morning and afternoon. And on the Day when the Hour will be established (it will be said to the angels): ‘Cause Fir‘awn’s (Pharaoh) people to enter the severest torment!’” [Ghaafir 40:46]
For the one who passes the test in the grave, the reckoning in the Hereafter will be easier for him. 
It was narrated that Haani’ the freed slave of ‘Uthmaan ibn ‘Affaan said: when ‘Uthman ibn ‘Affaan stood by a grave he would weep until his beard became wet. It was said to him, “You remember Paradise and Hell and you do not weep, but you weep because of this?” He said, “The Messenger of Allah (peace and blessings of Allah be upon him) said: ‘The grave is the first of the stages of the Hereafter; whoever is saved from it, whatever comes afterwards will be easier  for him, but if he is not saved from it, what comes afterwards will be worse for him.’” And the Messenger of Allah (peace and blessings of Allah be upon him) said: “I have never seen any scene but the grave is more frightening than it.” 
Narrated and classed as saheeh by al-Tirmidhi (2308); classed as hasan by al-Albaani in Saheeh al-Tirmidhi. 
The second stage of the reckoning will be after the Resurrection in the Hereafter; this is the great reckoning in which the people of Paradise will be distinguished from the people of Hell, and all scores will be settled along people. That Day is called the Day of Reckoning. 
Allah, may He be glorified and exalted, says (interpretation of the meaning): 
“This it is what you (Al‑Muttaqoon — the pious) are promised for the Day of Reckoning!” [Saad 38:53] 
“Moosa (Moses) said: ‘Verily, I seek refuge in my Lord and your Lord from every arrogant who believes not in the Day of Reckoning!’” [Ghaafir 40:27]
No one will enter Paradise or Hell until after this reckoning. Some people will have an easy reckoning, and some will have a difficult reckoning. Our Prophet Muhammad (peace and blessings of Allah be upon him) will be the first one to enter Paradise in the full and real sense in the Hereafter. 
It was narrated from Anas ibn Maalik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: “I will come to the gate of Paradise on the Day of Resurrection and will ask for it to be opened. The keeper will say: ‘Who are you?’ I will say, ‘Muhammad.’ He will say: ‘I was commanded not to open it for anyone before you.’” Narrated by Muslim (193).  
Secondly: 
With regard to the ahaadeeth in which the Prophet (peace and blessings of Allah be upon him) said that he saw someone in Paradise or in Hell, these are of two types: 
1 – Either they were dreams, as in the hadeeth of Abu Hurayrah (may Allah be pleased with him) according to which the Prophet (peace and blessings of Allah be upon him) said to Bilaal at the time of Fajr prayer: “O Bilaal, tell me of the best deed you have done in Islam, for I heard the sound of your sandals in front of me in Paradise.” 
Al-Haafiz ibn Hajar said in Fath al-Bari (3/35): 
Al-Karmaani said: The apparent meaning of the hadeeth is that the hearing mentioned happened in a dream, because no one can enter Paradise except after death. The idea that it happened in a dream is supported by that which is quoted in the first part of (the chapter on) the virtues of ‘Umar from the marfoo’ hadeeth of Jaabir: “I saw myself entering Paradise and I heard footsteps, and it was said: This is Bilaal. And I saw a palace in the courtyard of which there was a girl, and it was said: This is for ‘Umar. …” After this hadeeth is the marfoo’ hadeeth of Abu Hurayrah: “Whilst I was sleeping I saw myself in Paradise, and I saw a woman doing wudoo’ beside a palace, and it was said: This is for ‘Umar. …” So it is known that this happened in a dream. This affirmed the virtue of Bilaal, because the dreams of the Prophets are wahy (Revelation), hence the Prophet (peace and blessings of Allah be upon him) affirmed that for him. End quote. 
2 – Or Allah showed His Prophet (peace and blessings of Allah be upon him) what would happen in the Hereafter, so that he saw it with his own eyes or in his heart. That includes things that the Prophet (peace and blessings of Allah be upon him) saw on the night of the Mi’raaj of things that would happen in Paradise or in Hell. Al-Haafiz al-Nawawi (may Allah have mercy on him) said in Sharh Muslim (6/207): 
al-Qaadi ‘Iyaad said: The scholars said: It may be understood as meaning that he saw it with his own eyes, as Allah showed it to him and lifted the barrier between him and it, as He showed him al-Masjid al-Aqsa when he described it. 
They said: Or it may be understood as meaning that he saw it by way of knowledge and revelation, so he saw it and learned of it in details that he had not known before that. 
Al-Qaadi said: The first interpretation is more likely and is closer to the wording of the hadeeth, because it contains things that point to seeing with the eyes, such as his reaching out to take the bunch of grapes, and his stepping back in fear lest the heat of Hell reach him. End quote. 
See also the answers to questions no. 4003, 5643, 12478 and 14526. 
And Allah knows best.