Question

What are the core beliefs of Islam?

What is the God(s) or Supreme Being(s) of Islam?

What are the Religious practices/laws of Islam?

Answer 1

CORE BELIEFS Belief in Allah as the one and only God
Belief in angels.
Belief in the holy books.
Belief in the Prophets...
Belief in the Day of Judgement... ...
Belief in Predestination...

GOD(S) OR SUPREME BEING(S)
Islam. Islamic scholars have used the term Supreme Being to refer to Allah, Arabic for "The God".

RELIGIOUS PRACTICE 
Sharia is the religious law forming part of the Islamic tradition

Answer 2

Islam has only one god and the last messenger is Muhammad (SAW)