Would you explain your reasoning? I have seen no evidence of an agenda or goal; I also see no likelihood of 'abandonment' of the host bodies. In fact, I foresee them wanting to remove themselves, and discovering that they cannot do so ...
For me, the agenda/goal concept primarily comes from Miles Lanier's briefing - particularly the part about hacking into NeoNET and sending the memo to those recipients (Abigail James, Nightengale’s Clinics; Finion Elparanza, Dorada Genetech; Aston Faust, Pioneer Cybernetics; John Bogden, MindStorm Neurotechnologies; Teng Suzhou, Suzhou Biotechnology) - quite possibly fellow Fragmented/Inhabited. Also the account of those three people at the NYE party, and SEARCH's demands on FastJack(SR). Trying to get all Fragmented/Inhabited to get the same augmentations suggests they're shooting for something specific, yet to be revealed - but they don't get biology (yet). They don't get that the people they're in aren't the same as them. SEARCH taunted Fastjack about not "getting attached to this shell" - to me this implies SEARCH thinks FJ is another Fragmented/Inhabited who happened to get in first, and SEARCH has no problem about evicting him, provided the nanohive and genewipe are in place. Another point of interest is why SEARCH didn't contact MindStorm during one of the blackouts FJ had . . . correction: SEARCH did try to access MindStorm, presumably to arrange to get those augmentations.
I don't agree with the theory that Danielle de la Mar and her backers knew about all this and designed the new [SR5] Matrix to work against these entities. De la Mar just comes across as incredibly "I know what's best for the world, so you should all do what I say" - annoying, sanctimonious, holier-than-thou - but she really believes the line she's pushing/selling.