I have always agreed with the two generation scenario -- that Francis, Jr., married Hannah Bailey, and that Sr. (the immigrant) only married once -- to Anna (last name unknown).
To make things worse, because of the confusion, one finds some obvious duplications in children -- that is, children listed as by Sr., who seem to properly belong to Jr., and in some instances are listed twice.
There is NO way it works with Hannah Bailey as the wife of Sr., given the ages.
I think the confusion stems from the interchangeable usage of Anna and Hannah. Apparently, in those days, the "h" of "Hannah" was silent, and thus pronounced like "Anna". Think for instance of the pronunciation of "Honor".