Answer 1:
"Let there be no compulsion in religion: Truth stands out clear from Error..." [Quran, 2:226]
"Say, 'The Truth is from your LORD': Let him who will believe, and let him who will reject it..." [Quran, 18:29]
"Say: 'O ye men! If ye are in doubt as to my religion, behold! I worship not what ye worship, other than Allah. But I worship Allah - who will take your souls at death: I am commanded to be in the ranks of the believers." [Quran, 10:104]
Quran have not a single verse what says apostasy penalty is death but this is mentioned in Haddith (*though many haddith are not true) because God's previous law Torah have a similar commandment. It says, if anyone leave his/her religion or worship other gods then he/she must will be put to death.
***The law of Apostasy is mentioned in Bible and not in Quran:
"If your very own brother, or your son or daughter, or the wife you love, or your closest friend secretly entices you, saying, "Let us go and worship other goes" [Deut, 13:6]
"gods of the peoples around you, whether near or far, from one end of the land to the others,)" [Deut, 13:7]
"Do not yield to him or listen to him. Show him no pity. Do not spare him or shield him." [Deut, 13:8]
"YOU MUST CERTAINLY PUT HIM TO DEATH. YOUR HAND MUST BE THE FIRST IN PUTTING HIM TO DEATH, and then the hands of all the people." [Deut, 13:9]
"Stone him to death, because he tired to turn you away from the LORD your God..." [Deut, 13:10]
During the life times of Prophet(Pbuh), few Pagans (of Mecca) converted to Islam only for do something against of Islam or try to killing our Prophet(Pbuh) and later they changed their religion. This made a problem for Muslims. So Prophet (Pbuh) commanded that apostasy penalty is death according to Torah because it was a necessary law to solve that problem.
Answer 2:
He didnt. ***Wife beating is not allowed in Islam:
Quran, 4:34 literally mean "hit or leave them" and Prophet Muhammad(Pbuh) teaches dont beat your wife.
Narrated Mu'awiyah al-Qushayri: "I went to the Apostle of Allah and asked him: what do you say (command) about our wives? He replied: Give them food what you have for yourself, and clothe them by which you clothe yourself, AND DO NOT BEAT THEM." [Sunnah Abu Dawood, Book 11, Marriage, Number 2139]
Prophet Muhammad says act kindly towards women. (Sahiah Bukhari, book 8, Number 3468)
"O ye who believe! Ye are forbidden to inherit women against their will. Nor should ye treat them happiness, that ye may take away part of the dower [i.e money given by the husband to the wife for the marriage contract] ye have given them, except where they have been guilty of open lewdness: on the contrary live with them on a footing of kindness and equity. If ye take a dislike to them it may be that ye dislike a thing, and God brigns about through it a great deal of good." [Quran, 4:19]
***Wife beating is not allowed in Islam in any case! http://www.answering-christianity.com/beating_no.htm (click here).
Answer 3:
No. Quran have not a single verse what says about the stoning. Adultery is a shameful deed, this is mentioned in Quran. Adultery penalty is not mentioned in Quran.
"Nor come nigh to adultery: for it is a shameful (deed) and an evil, opening road(to other evils)." [Quran, 17:32]
***Steal penalty is mentioned in Quran but that is not stoning.
"As to the thief, Male or female, cut off his or her hands: a punishment by way of example, for their crime. And God is exalted in power. But if the thief repents after his crime, and amends his conduct, God turneth to him in forgiveness; for God is oft-forgiving, Most Merciful." [Quran, 5:38-39]
My response to you:
Well. You may seek the truth. If you have any question against of Quran then you are always welcome and feel free to ask me. Hope you will accept the truth of Islam.
Islam mean "submission to God" and this is the religion of all Prophets and Prophet Muhammad is the last Messenger of God.
Meaning of Muslim "one who submits their will to God." Before all Prophets and their true followers were also Muslim.
***Islam is the only true religion of God:
"Surely the true religion with God is Islam.." [Quran, 3:19]
"O ye who believe! Fear Allah as He should be feared, and die not except in a state of Islam." [Quran, 3:102]
"If anyone desires a religion other than Islam (i.e submission to God), Never it will be Accepted of God, and in the hereafter he will be in the ranks of those who have lost(all spiritual good)." [Quran, 3:85]
"Let there be no compulsion in religion: Truth stands out clear from Error..." [Quran, 2:226]
"Say, 'The Truth is from your LORD': Let him who will believe, and let him who will reject it..." [Quran, 18:29]
"It is He(GOD) who hath sent His Messenger (Muhammad) with guidance and the Religion of Truth, TO PROCLAIM IT OVER ALL RELIGION, even though the Pagans may detest this religion." [Quran, 8:33]
***This is a clear promise of God, Islam will proclaim over all religion:
1. CNN - Fast-growing Islam winning converts in Western world - Apr. 14, 1997 http://www.cnn.com/WORLD/9704/14/egypt.islam/ (click here)
2. NBC news: 20000 Americans convert to Islam each year! http://m.youtube.com/watch?gl=US&xl_blz_on=xl_blz_on&client=mv-google&hl=en&v=Rfx4glTU5JQ (click here)
This is the last verse of Quran:
"..This day have I perfected your religion for you, completed My Favour upon you, and have chosen for you Islam as your religion.." [Quran, 5:3]