You mentioned: The somanassa vedana is indeed produced by “samphassa with gati”. The gati in this case are not just with the Arahant, but anyone in human bhava. “Sweetness in sugar” is a “human gati”; see the post on Kama Guna. For the Arahant, that gathi will also go away at Parinibbana; it is there only as long as that last human body is alive.
Does this mean that the Buddha also had gati since He was in the human bhava in his last life? But as I seem to recall, you stated in another post that the Buddha did not have any defiled habits remaining, unlike an Arahant. Are gati also defiled habits?
Also, as I understand it, somanassa vedana are mind-made feelings or mentally fabricated feelings. Am I wrong? Why would an Arahant mentally fabricate feelings?
Thank you very much in advance for your answers to my questions.