Looking at the image of the 1870 census record on familysearch, comparing W's and M's, the diacritic dots (2 each) and their offset placement over both Higgins and his first name, and (more importantly) lower-case r's, it appears to me that the entry was intended to be "Higgins Willie F" I.e., the second diacritic dot over his first name would indicate that an i (eye) was intended.
Further, other lower-case r's in that record (e.g. two instances of "laborer") are different than the last letter in the first name.