Well an early 1970's legal proceeding helps to explain the infamous airport photos.
The idea is that something like the following might have transpired:
1) Barack Jr may very well have been born out of wedlock in 1961, and Barack Hussein Obama Sr's name may not have appeared on the original birth certificate [wherever that birth certificate was issued - in Hawaii, or in the state of Washington, or in Canada, or who knows where - maybe Kenya or Japan?], and 2) No matter what information was listed on the original 1961 birth records, it was all sealed up in the circa 1965/1966 Soetoro adoption, and
3) When Stanley Ann wanted to send Barack home to be schooled in Hawaii, in the early 1970's, she knew that she would need to get her parents, Madelyn Payne Dunham & Stanley Armour Dunham, to agree to become the legal guardians, and so Stanley Ann realized that she would have to go back to court to get the circa 1965/1966 Soetoro adoption rescinded, and so
4) Stanley Ann asked Barack Hussein Obama Sr to fly in from Kenya to testify to the court that in fact he was the birth father, not Lolo Soetoro.
Ergo the infamous early 1970's airport photographs:
When Stanley Ann wanted to send Barack home to be schooled in Hawaii, in the early 1970's, she knew that she would need to get her parents, Madelyn Payne Dunham & Stanley Armour Dunham, to agree to become the legal guardians, and so Stanley Ann realized that she would have to go back to court to get the circa 1965/1966 Soetoro adoption rescinded, and so 4) Stanley Ann asked Barack Hussein Obama Sr to fly in from Kenya to testify to the court that in fact he was the birth father, not Lolo Soetoro.
In a guardianship procedure, it's the adoptive parent who would have to give consent -- not the birth parent, who has already surrendered parental rights by virtue of an adoption. It was Lolo that would need to consent, not Obama, Sr., but neither Lolo or Ann would have had to surrender their parental rights to allow the Dunhams to assume guardianship, if, in fact they did.
You seem to be working backwards from conclusions that a) she was trying to sever ties with Lolo, in spite of the fact that there's evidence she did no such thing until 1980, when she filed for a divorce she never finalized; and b) those airport photos must have some significance other than a visit from the birth father.
Again, Ann, who was not exactly a balanced individual, continually encouraged Barry to take pride in his African heritage while he was living in Indonesia, to the point of obsession -- so, inviting his birth father (who had just spent almost a year in the hospital, losing his leg in a drunken car accident that killed a civilian) to Hawaii, is just the sort of bizarre thing she would have done. She might even have paid for the plane fare, on Lolo's dime, since according to "Dreams," Obama's African half-sister told him that Obama, Sr. was broke and unemployed at the time. I doubt Madelyn Dunham was thrilled about it either -- the visit ended in a major family argument, according to the book.