Review notes are stored as annotations, separate from the page. They keep the text of each note, the name of whoever wrote it and when — and they are easy to forget, because a reader only shows them when you turn comments on.
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Anything a reviewer adds on top of the page: sticky notes, text boxes, highlights, underlines and strike-through, freehand drawings, stamps, and replies to another note. Each one can carry an author, a timestamp and its own appearance, and the text of a deleted paragraph sometimes survives inside one.
Links to websites are annotations too, but they are part of how the document works, so they are kept unless you say otherwise — and their addresses are shown, because a link can carry tracking codes. Form fields are listed separately: you can empty them, flatten them into the page, or leave them editable.
You decide per item in the review step; the report then shows, for each one, what happened to it in the copy that was made.
Yes — they are removed from the document, not hidden. The new copy is reopened and scanned again, and the report lists the comment text that is no longer found.
No. A highlight is itself an annotation; removing it takes the coloured mark away as well as the note attached to it.
Strike-through is a mark on top of the page; the text underneath is still real text. If you want that text gone, remove it as personal information or as your own search term.