I have few questions please reply soon,
1) Can women do Imaamat?
2) Can women do prayer behind a man in same room?
3) How many Raka'h in Jumu'a prayer? (I am living in UAE. Here everyone do 4 Sunnah, 2 Fardh, 2 Sunnah), but in Pakistan we do 4 Sunnah, 2 Fardh, 4 Sunnah, 2 Sunnah, 2 Nafilah) which is correct? Please tell with the reference of Hadith.
4) What do you think about the 4 Imaams. Somebody told me these are Firqah is that right?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

It is permissible for a woman to lead other women in prayer and this matter is not disliked according to the most preponderant opinion of the scholars. Um Waraqah narrated that the Prophet ordered her to lead the women in her household. [Abu Daawood]. However, it is not permissible for a woman to lead men in prayer according to the most preponderant opinion of the scholars.

It is permissible for her to be led in prayer by a man even if he is a marriageable person to her provided there is no seclusion. Nonetheless it is more appropriate if one of her or his Mahaarim (unmarriageable relatives) is present. The evidence about this is the narration of Al-Bukhari and Muslim that the Prophet led the prayer with Anas Ibn Maalik who said: "I and an orphan stood behind the Prophet and a lady stood behind us. He prayed two Raka's then he went away." 

As regards the number of obligatory Raka's of Jumua'h prayer it is two, without a difference of opinion among the scholars and a Muslim does not have to pray other than these two Raka's. Jumua'h prayer has no optional Sunnah prayers before it but a Muslim can perform any number of supererogatory prayers as he wishes. However, some scholars including some from the Hanafi School, are of the view that one can pray 4 Raka's, before Jumu'ah and they provided a weak narration as evidence.

The Islamic Jurists differed as to how many Raka's should be prayed after it. The most preponderant opinion of the scholars is that if a person prays in the mosque he should pray 4 Sunnah Raka's and if he prays at home, then only two. This is the view that encompasses all the evidences in the matter. For instance the Prophet said: "Whoever wants to pray after Friday prayer, has to pray 4 Raka's." [Muslim] Abu Daawood reported that the Prophet used to pray 2 Raka's after Jumua'h in his house.

Concerning the four Imaams they are Imaams of guidance and much good. They do not have any differences of opinion regarding the principles of religion. However, they differed in some branches (in minor issues) not for the purpose of differing but due to many reasons. For instance, they differed in their understanding of some texts. Nevertheless, one could condemn the fanaticism that appeared after them which led to hatred and division among the Muslims. It might be that those who are of this opinion mean the understanding and meaning that we have put forward. 

Allaah knows best.