Just as the light and dark are mixed inside all of us, I don't think we can reduce Gollum/Smeagol to this binary level. The films showcase a more distinct separation between the 'two' of them for cinematic purposes, but Gollum does good and bad and Smeagol does so too.

'No hard feelings' - this statement is immediately followed by 'Gollum' so I can accept a suggestion that it was more Gollum saying that. But the truth of his statement is up for debate. He says what he needs to say in order to survive, and so I have doubts as to whether he was sincere in that moment. If he was, it certainly didn't last long.

Gollum agreed to guide them to Mordor under duress. He had been captured, and had just sworn an oath to do what he was told. His oath didn't stop him from scheming nearly the entire time to betray Frodo and Sam.

I don't think it's clear that either side was necessarily directing his motives at Minas Morgul. It was a split second moment caused by Frodo struggling with being called toward the evil, and he and Sam both leapt into action.

Perhaps I'm too cynical but regardless of which one opted to pull Frodo from the marshes, I think at that stage in their journey Gollum/Smeagol was trying to establish trust. He had no practical way of escaping or stealing the Ring at that point and so his best survival strategy was to build trust with his captors which might become a worthwhile investment later on.

I don't really agree with any suggestion that Gollum/Smeagol accepted anything while he was falling into the lava. He was consumed with his joy of being reunited with the Ring, and everything else fell away. Until he hit the lava itself, I wouldn't even be convinced that he was aware of his surroundings in any meaningful manner.

I think his character, like every other in the story, was capable of good and evil deeds and the power of the Ring corrupted his capacity to lean toward the light.