Assalamu alikum , Our Masjid is small to have all Musalli in one time on Friday.

 1-Can we pray Friday prayer before entering into Duhor time?

 2- If we can`t then can we Do Friday Khutbah before Duhur time, for some brother told that he saw some Masjid in USA doing that?

 3-We have huge school, Can we leave Masjid and pray Fiday prayer in that school. Please , reply me with Shari`ah evidances for I am Imam of that Masjid. Wa Jazakum Allahu khairan. Tel-901-428-1831

All praise be to Allah, and may his peace and blessings be on the last and best prophet and messenger, Muhammad.

As for praying more than one jumu`ah in the same place:

This is only allowable in case of a legitimate need, according to one of three opinions, which are:

Never allowable

Always allowable, upheld by `Ata`, Ibn Hazm and others.

Allowable for a legitimate need

The third seems to be the one most consistent with evidence, since the Prophet and his righteous successors never had more than one jumu`ah in the same town, yet when the size of Baghdad grew to a point it was not possible to have one jumu`ah for the whole city – as reported by al-Khateeb al-Baghdadi -, they prayed two, without condemnation from the contemporary scholars of the time. It is also important to say that the Prophet (May Allah bless him and give him peace) never condemned praying in two masjids, and the case of masjid al-diraar must be understood within its entire context of some hypocrites wanting to divert people away from the Messenger of Allah.

In your case, you seem to have a legitimate need. The fear from not allowing multiple jumu`ahs in the same town is that many people will fail to pray and gradually will be disinterested in coming to the jumu`ah. This can have serious negative repercussions on the Muslim minorities.

I should, however, say that the community must work to enlarge the masjid or obtain a larger one, so that this out of the ordinary position may be resolved.

As for the time of Jumu’ah:

In the Hanafi and Shafi`i madhhabs, the time for Jumu`a is the same for dhuhr prayer, which is from noon until `Asr.
In the Hanbali madhhab, the time for Jumu`ah is the same for Eid prayer, which is from Duha, approximately 15 minutes after sunrise, until `Asr. The proof of the hanbali position is the following hadeeth:

Muslim reported from Jaabir ibn Abdullah, in the `Book of Jumu’ah`

‏كنا ‏ ‏نصلي مع رسول الله ‏ ‏صلى الله عليه وسلم ‏ ‏ثم نرجع فنريح ‏‏ نواضحنا ‏ ‏قال ‏ ‏حسن ‏ ‏فقلت ‏ ‏لجعفر ‏ ‏في أي ساعة تلك قال ‏ ‏زوال ‏ ‏الشمس

 "We used to pray [Jumu`ah] with the Messenger of Allah (May Allah bless him and give him peace) and then we would go back and rest our camels. Hassan said to Ja’far, at what time? Ja’far said, by noon"

So, based on that hadeeth, and this understanding of the hanbali scholars, it is permissible to pray Jumu’ah that early.

As for praying at the school, that is certainly a good solution, since it will enable you to perform one jumu`ah together, which is the optimal choice.

I would also use this dilemma to encourage the congregation to build a bigger masjid.

Allah knows best.