About this bit:
There is a good reason for the difference. The AV/KJV Greek text reads the italicised words as follows:
- POIOUSINTASENTOLAS
whereas the RV & NIV read:
- LOUOUSINTASTOLAS
Early manuscripts (until about 400 IIRC) were written in columns, in CAPITALLETTERSWITHOUTABREAK - & several of these capital letters are easily confused. In the present example, tas entolas (āthe commandmentsā) is easy to confuse with tas stolas (āthe robesā). They look similar - & mean utterly different things.
A further mistake is to take a translation as the standard for the readings of the Greek text - as should be obvious. Unfortunately, translations have a tendency to be treated as āthe Bibleā - when they are more or less imperfect translations of it.
And most Christians do not know much, if anything, about textual criticism; so it is only to be expected that they should be suspicious of unfamiliar translations of much-loved phrases. That does not make the familiar phrases accurate renderings of the Greek or Aramaic or Hebrew texts of the Bible.

This kind of pious ignorance is not new - the Vulgate took some getting used to, as did the AV.
Whether a translation āsupports the doctrines of Romeā is neither here nor there; what matters is that it should be as accurate & faithful as possible. In any case, the NT is very āproto-Catholicā in some respects; just as it is āproto-Calvinist/Anglican/whateverā in others. It is absurd to expect that Godās Word should accommodate itself to our biases - our business is to be renewed in our minds so that we can escape our biases & have the mind of Christ instead
As David Payne, a British Evangelical, pointed out 30 years ago, it could be argued that the two readings in the RV & NIV are more Evangelical than the ones in the AV/KJV