Why should she have been a part of Houdini? The purpose of Houdini was to hide people living on Mesa who would be vulnerable when Manticore inevitably came to call.
I don´t think that is correct. The plan is apparently part of the LONGterm planning, which means current events are not what was expected.
The plan is meant to get MA personnel to disappear without seeming to disappear.
This part of the planning is repeatedly emphasized in the books. If the goal was merely to make sure that invading manties couldn´t catch them right in the here and now, there would be no need for all the elaborate scheeming to make it seem that all those people died natural deaths.
O'Hanrahan is not part of Houdini because
(1) she is not potentially "trapped" on Mesa -- she has her own transport
Irrelevant, the same is true for others that are part of Houdini .
(2) she is not a perceived threat to either the SL, Mesa or the GA (other than a newsie's power of the pen)
And you expect that to remain so if she comes in contact with treecats why exactly?
(3) few on (or off) Mesa know she is a starline
Completely irrelevant. Genetic lines are merely assets to the MA, individuals of a line are as valuable as they make themselves.
(4) officially she is an independent Solaran journalist and commentator
And? That makes any difference because?
although I think Alfredo might detect many inconsistencies by listening to any conversation with her
Exactly, and she is one of few that DO know much.
Plenty enough to cause at least minor troubles for the MA if she gets caught.
Which is why it would make perfect sense that she is there to be "a dreadfully tragic victim of the nasty ballroom barbarians with their blatant ties to imperialist Manticore"...
If she gets killed before her reputation is killed, she could definitely be the perfect powderkeg trigger a la Franz Ferdinand style, and since RFC likes to take inspiration from history it would even be inline with normal for him.
Which would make her instructions of what hotel to stay at and where to go a lot more sinister.