I am taking pleasure in this discussion, and hope I've engaged in a respectful manner.
Of course, I have thoughts
...
As am I. You have definitely been respectful. I know I have a tendency to sarcasm, so thank you for being patient. I was hoping you would have thoughts.
from the human perspective, there are good things and bad things in nature with respect to their effect on humans
But it seems like we can only know which things are good things, and which are bad things, by reference to pleasure or pain. Not sure if you are heading somewhere with this. I don't disagree though.
I found the LSJ definition of αγαθός instructive in that it used words like benefit to define the word. A "good thing" provides a benefit of service. That's why other schools can say virtue or reason are "good things."
"Ben-" is just the latin root for good, though, right? That seems circular, unless you now want to define benefit...
pleasure is the ultimate motivation underpinning all....
You said this didn't seem right, but you could meet my criteria by saying goods are things that are pursued/sought/desired. Pleasure certainly qualifies there, as do the instrumental goods. I still prefer my way of putting it, because it seems simpler, but if you needed a definition of good that non-Epicurean would accept without immediately giving away the game, this might be it.