About the Transwarp beaming, I have no doubt that Starfleet would have detailed scans of Kronos' surface by 2259. Beyond that, all they'd need to know it's orbit and can beam away. The risk being if someone was standing where you plan to materialize or if they'd done some contstruction work since the last scans were made (no doubt partly why Harrison chose an uninhabited area as his destination)
And about Khan's blood and the technology of the 1970's, I am reminded of DTI: Watching the Clock
's speculation that the Chrysalis Project may have had some assistance from the future.