They are still characters and there is a link to the Corriepedia articles on the page. You could say the same about Alan Sugar. These should be kept as they are a record of their appearance no matter how brief, their biography would only reflect their time in the special. For example see https://tardis.fandom.com/wiki/Pat_Butcher
That sucks, was looking forward to next week's episodes as Phil's coming back. Hopefully this coronavirus outbreak is dealt with sooner rather than later, that way we can get 4 EastEnders episodes a week again.