Did it! (UE4.19)
Your guys problem seemed to be that you tried to map a Key that was already mapped! Note that the .ini files have multiple versions that are MERGE TOGETHER according to the hierarchy. Then the merged version is parsed. So you basically try to add to bindings to the same key. Means you need to eliminate the registration line from the previous .ini files.
https://docs.unrealengine.com/en-US/…les/index.html
…/YourProject/Config/DefaultEditorPerProjectUserSettings.ini
[BlueprintSpawnNodes]
; Remap the slow DoOnce to a faster version
-Node=(Class=DoOnce Key=O Shift=false Ctrl=false Alt=false)
+Node=(Class=DoOnce_Fast Key=O Shift=false Ctrl=false Alt=false) ; custom node in MacroLibrary (Asset)
; Remap the useless P to to PrintString
-Node=(Class=Actor:ReceiveBeginPlay Key=P Shift=false Ctrl=false Alt=false)
+Node=(Class=PrintStringDebug Key=P Shift=false Ctrl=false Alt=false) ; custom node in BlueprintFunctionLibrary (Asset)
; Remap A to String::Append node
-Node=(Class=KismetArrayLibrary:Array_Get Key=A Shift=false Ctrl=false Alt=false)
+Node=(Class=KismetStringLibrary:Concat_StrStr Key=A Shift=false Ctrl=false Alt=false) ; C++ function