Addition of Mark 16.9 to 16.20, do not in any way lead to any new twist to the event of Resurrection in Bible vis-a vis its depiction in other Gospels. This applies to all other citations in the question also
All these citations do not change or contradict any belief within Bible. We could have argued against these additions, had it been something entirely new and not in consonance with other Gospels and if it is something very much contradictory to some other verses at some other place. The fact that the earlier version exists and points to these citations as “additions” without actually contradicting any other verses or messages, only strengthens the veracity of the Bible that it has withstood test of time.
It has proved that there were no attempts to change its central message as depicted by different Gospels “BY ADDITION OF THESE NEW VERSES” and
Most importantly it has also proved that there are "NO REMOVAL OF VERSES FROM ORIGINAL MANUSCRIPT" for being contradictory with what has been already revealed or written.
I need not mention here that it is more serious and pure forgery if any verses are found “removed” from any original versions of any book (Not restricting this only to Bible)(reminds me of satanic verses issue) for being contradictory. If the original verses are itself removed from a book for being contradictory, then everything for which that book stands for, is in doubt. Under this instance, the book will have no authority to contradict its detractors.
In brief the above cited addition are not at all affecting any of the truth for which Bible stand for:
Mark 16.9-11are the same events mentioned in Luke 24.1-12, though summarised form.
Mark 16.12-13 also summarises the same events as are mentioned in details in Luke 24.13-32.
Mark 16.14 is the rebuke of his disciples for their doubting which is mentioned in more details in Luke 24.36-43
Mark 16.15.20 is the commissioning of his disciples for teaching the Gospel to all nations which is same as mentioned in Luke 24.44-49.
Luke 22.43-44 is an observation that is similar to Mathew 26:37 and Mark 14:34 and is nothing new in the whole context of Jesus’ suffering in Gethsemane. This only depicts the great spiritual struggle Jesus was passing through.
John 7.53-8.11 is not at all contradicting anywhere with what Christ taught in his entire ministry on this earth. (Case of prodigal son Luke 15.11-32)
1John5.7-8 addition is also not something new but found woven through all of Scripture from Genesis to Revelation. The idea of Trinity is in no way dependent on this verse but there are explicit references to Trinity at umpteen places and more distinctively at Mathew 28.19, John 14.26, John 15.26 Mathew 1.18, 1 Corinthians 12.3, 2 Corinthians 3.18, 2 Corinthians 13.13, Ephesians 2.18.