What is the ruling on forgetting to mention that an article is نقل (transferred/republished) or forgetting the author's name when transferring an article with the intention of benefiting others, given that the author did not state her disapproval of such transfer?

There is no harm in quoting articles, fatwas, or beneficial information from books and websites, provided that they are attributed to their authors or original sources. Forgetfulness is an acceptable excuse, but academic integrity requires attributing the material to its author or source, and this can be remedied later.