These components would have been sterilized by the solar wind. Any DNA that would have existed in what would have been living cells that may have survived the trip out of the atmosphere would be blasted in to incoherent and inert dust by the solar wind within short period of time unless shielded by being buried very deep inside a very large rock.
Any rock large enough to be shielding for life would be superheated by impacting a wandering planet again destroying that life.
The idea that a wandering lifeless planet could pick up life by drifting by a life bearing planet seems to me pretty far fetched.
“Any rock large enough to be shielding for life would be superheated by impacting a wandering planet again destroying that life.”
The rock heats on the surface and upper layers while remaining cold in the inner areas. The heat of resulting from friction upon atmospheric reentry most often causes the rock to fracture and breakup during reentry, leaving the cold interior portions of the rock relatively unsscathed and fallin to the surface exposed and relatively undamaged by any heat. In many cases, it is almost as if the process worked as a seeding process.