The word you are referring too in Surah Al-Ahzab Aya 45 is mu bashshir an. It is not the same as Injeel which is generally translated as gospel.
The Prophet did NOT preach a so-called gospel (Injeel) that was any different than what previous revelations revealed...
Galatians was written by Paul who was NOT a prophet or law-abiding moomin. Paul did not receive revelations that he successfully preserved from Malaikatu Jibreel (angel Jibreel) either.
Better learn some Hebrew or Aramaic man...

The Hadiths that you mentioned which are obviously without context are nothing worse than many of the supposed stories in the Bible's New Testament and Old Testament (compiled at the Council of Nicea by Romans without regard for the local Palistinian tribes and village's consent).
Articles like this are used to spread propaganda and it sucks because if you were more properly informed and knew how to write a better article on you may succeed.
Anyways all praises due to the Most High may the Most High bless you with knowledge, patience, and sincerity.