There are several issues with that harmonization. From the start we see the author of the article you quoted didn’t even bother dealing with the issue of the stone.
In Mark, Mary Magdalene, Mary mother of James, and Salome went to the tomb. As they were going there they asked who would roll the stone away. They were surprised that it was already moved away when they got there. In Matthew, Mary Magdalene and the other Mary went to the tomb and the stone was not rolled away. There an angel rolled the stone away then sat on top of it.
In sum, there can never be a harmonization because in one Gospel the two Marys go to the tomb wondering about moving the stone then see it already moved when they get there, but then in another they get there and see an angel move the stone for them. Even by adding to scripture by saying there were multiple visits, at no point would either be surprised the stone’s moved in one and see it moved in another.