Dear Max: I do not pronounce "roof" the same as "hoof". For me the first has a longer "oo" sound than the second. "hoof" and "crook" are the same. I have never heard or seen,nor does my dictionary give "rooves".
My dictionary gives both "dwarfs" and "dwarves", but I don't remember hearing the second pronunciation.
But with "wharf" the plural I am used to is "wharves.