I will just add here that "Friend of peace" basically is just translating a common Hebrew idiom "son of peace" or as Cambridge puts it " a son of peace, i.e. a man of peaceful heart. Comp... Luke 16:8, Luke 20:36; John 17:12; Ephesians 5:6; Ephesians 5:8."
(https://biblehub.com/commentaries/luke/10-6.htm)
does "son" always literally mean "son" - well kind of, it means literal offspring but can also mean the idiom or in other words "son of specified group" - you are "ruled" or "parented" by the modifying noun.
In this case a peaceful man.. "a friend of peace" while not a literal translation is justifiable based on not only context but also the meaning to the idiom.. but then again if we take one look at the KJV or NIV we will find quite a few non-literal translations in other places.
Just because the NWT is a "literal" translation, does NOT mean it will translate everything literally.. (research how translation works.) When needed it may need to clear up the meaning of the text for English readers - We know where literal translations get us with the NWT, stilted and wooden translations which others complain about. This argument may sound familiar, and it should be I'm recycling an older argument used on ones who did the same with "theos" in 1:1c (The ONLY singular, nominative, non-prepositional instance of Theos in 1)
NIV uses "someone" that's not a literal translation of the word "huios", is the NIV wrong? no - nor is the NWT
"a friend of peace" simply means the same as "son of peace" but is a better word picture in English, someone who is peaceful or who likes peace, exactly what this verse is trying to convey.
Lets look at John 18:37, you would be out of your mind to say the NWT translates this wrong. the literal text (in focus) is:
"“Ἡ βασιλεία ἡ ἐμὴ οὐκ ἔστιν ἐκ τοῦ κόσμου"
"By "of this world" we are to understand that the nature and origin of His kingdom are not of this world, not that His kingdom will not extend in this world."
(https://biblehub.com/texts/john/18-36.htm)
- or in other words as the NWT puts it "part of this world" Christs Kingdom is not from this world, nor has any involvement in it as can be seen from 6:15 and Jesus' actions.
breaking it down we have ouk meaning "not" "ek" meaning "out of" which is used in the sense of "part" as well in some cases and lit "the world"
If you want to try and this is a distortion, please go and learn Greek and how ek functions (not just for theologically important texts), as it functions in a variety of ways.
In sum does [Friend of peace] change the meaning? no, not really. If you want a hyper-literal translation, go and use one.. If you want a paraphrase go and use one.. (I use about 7 different translations) it is by far in the realm of a possible meaning of the text.
A T Robertson says "It means one inclined to peace, describing the head of the household." - consequently if you are inclined towards something, are you not technically a "friend" of it. (James 4:4)
anyone who says it (or John 18:36) is not, is either wilfully ignorant or just simply dislikes the NWT for some reason.. Which for the second, may I remind of Golden rule in the Bible?
sidenote: translate Eph 4:14 literally, then tell me the meaning has been changed or that any bible translation uses a literal translation (not one translates it "literally" - see: Strong's - not even the KJV does, which is odd as I expect it would)