Corrected entry: In 2014, Gamora and Nebula have a conversation after Ebony Maw announces that Thanos has found an infinity stone. They agree that finding one infinity stone is a start to Thanos' plan that has been set in motion. But in 2012 Thanos already had the Mind Stone which he lent to Loki to use to retrieve the Space Stone.
Corrected entry: When the Avengers got the space stone and mind stone from the past, they were in the form of the Tesseract and the scepter, but when Steve goes back to replace them, they are in their raw forms. If they want to undo any offshoot timelines, they would have to replace the time stones in their original encasements, at least some of which have been destroyed in the process of obtaining the raw stones. If the Tesseract doesn't exist in Tesseract form before Captain Marvel, would the light speed ship by Dr Larson have been made, etc. And the events of Avengers 1 would have been altered...Ultron/Vision/Scarlet Witch/Quicksilver timelines would likely be disrupted if the scepter itself is not replaced, only the mind stone. It would be an anomaly in the time line.Jeanne Rhodes-Moen