A genealogical chart in an article 'The Vernons of Haddon Hall' by John Pym Yeatman, in Journal of Derbyshire Archaeoligical and Natural History Society, vol. 15, agrees with the above, and it looks like what is on WikiTree confuses Robert de Vernon, son of Richard de Vernon, and Avice de Avenel, with his nephew, Robert de Vernon, son of William de Vernon and his 1st wife Margaret Stockport.
The two wives on the profile of Robert de Vernon, look like they are basically duplicates of the wives of his brother William, and I would delink them from Robert and merge them with profiles for William's existing wives if those profiles exist. The same for De_Vernon-87, I would merge it with. I haven't checked thoroughly but it looks like the name of Robert's wife is unknown, but he did only have one child, or surviving child, Hawise.