[Imladris]

Interesting questions.

I personnally think that Sam could have hurt Frodo. During the quest, he has grown from a relatively simple hobbit into almost a leader at the end of RotK. He was mainly the driving force of the quest. He also left Frodo for dead at Shelob and took the Ring. So, yes, I think that Sam would have had enough strength and perception (remember when he resisted the temptation of the Ring to become Samwise the Strong) to hurt Frodo to destroy the Ring.

I also think he would have been able to destroy the Ring for the same reasons.