The verse I supplied explicitly addresses the deity of Christ. If one is not worshipping Jesus Christ, he is not worshipping the Father. This applies to both Muslims and Jews.
These might even use the words of the Bible to reference "god". They might even claim they are looking forward to a messiah. But, if they deny that Jesus is the Christ (the Messiah), they do not have God. They do not have the Son. They do not have the Father.
Absolutely correct. Christ is the God of creation. Allah, in the Koran, is not Jehovah.