Just to add a small note to Venerable’s note on the three suttas:
The Sampasādanīya-sutta seems to be the earliest among the three. This has been already expressed by some scholars already. And also, the commentaries on the Mahāparinibbāna and Nālanda direct the readers to the commentary on the Sampasādanīya-sutta. So, the scholars who has expressed the former two to be latter actually seems to be correct in accordance with the commentaries on the two former suttas.
I think both the Mahāparinibbāna and the Nālanda do not have the complete version of the discourse. To me, the Sampasādanīya-sutta seems to be the discourse in its complete form, where Sāriputta discusses sixteen excellences of the Buddha – further, the sixteen are actually some very important topics in early Buddhism.