“Pleasing and agreeable things in this world that has Kāma Guṇa can evoke Sāmisa Vedanā in a person but never Kāma assāda, right?”
Yes.
“So, if a person who experiences Kāma assāda, does it imply that this person has already executed the samphassa-jā-vedanā process?”
No. Kāma assāda are, by definition, samphassa-jā-vedanā.
The Buddha would also taste honey as sweet. The sweetness of honey is a Kāma Guṇa.
– An average person may attach to the taste of honey and may generate greedy thoughts about tasting more honey. That is due to samphassa (“san” + “phassa”) or “contact with “san” or defilement (greed in this case)”
– But the Buddha (or any Arahant or an Anāgāmi) would not generate “samphassa-jā-vedanā” for eating honey.