pohaikawahine, I suggest you go through the thread for a clear picture. Hopefully you will find the answers to your questions already written in them. I'll take this opportunity just to recap slightly and add some more material to this thread.
All the Prophets and Messengers called humanity to worship Allah alone without ascribing to Him any partner, and they all submitted completely to the will of Allah, which is Islam. The Prophets, from Adam to Muhammad (peace be upon them) were all brothers in faith. They all called to the same truth. Here I relate some very relevant verses for your perusal which were not shown before.
Allah chose Adam, Nuh(Noah), the family of Ibrahim (Abraham) and the family of ‘Imran above the ‘Alamin (mankind and jinn). [Qur’an, 3:33]
And, verily, among those who followed his (i.e. Nuh’s (Noah’s)) way was Ibrahim (Abraham). [Qur’an, 37:83]
He (Allah) has ordained for you the same religion (islam) which He ordained for Nuh (Noah), and that which We have inspired in you (O Mohammad (pbuh)), and that which We ordained for Ibrahim(Abraham), Musa(Moses) and ‘Eesa(Jesus) saying you should establish religion (i.e. to do what it orders you to do practically), and make no divisions in it. Intolerable for the Mushrikun (those who worship other things than Allah), is that to which you (O Mohammad (pbuh)) call them. Allah chooses for Himself whom he wills, and guides unto Himself who turns to Him in repentance and in obedience. [Qur’an, 42:13]
Verily, We have inspired you (O Mohammad (pbuh)) as We inspired Nuh (Noah) and the Prophets after him; We (also) inspired Ibrahim (Abraham), Isma’il (Ishmael), Ishaaq (Isaac), Ya’qub (Jacob), and Al-Asbaat (the twelve sons of Jacob), ‘Eesa (Jesus), Ayub (Job), Yunus (Jonah), Harun (Aaron), and Sulaiman (Solomon), and to Dawud (David) We gave the Zabur (Psalms). [Qur’an, 4:163]
Some other relevant verses are 3:33, 7:59, 9:70, 46:21.
Hope this helped.
And Allaah knows best.