Can Scurvy and Drinking the Sea stop Bronn's ability's to save a character?

Bronn's ability doesn't save anything. The word "save" isn't used anywhere in the text. His ability creates a replacement effect. It is not a Save Response and has completely different timing.

So no, putting a "cannot be saved" condition on a character does not stop Bronn's ability.

What about Drinking from the Sea? If Bronn's ability is considered a replacement effect, would Drinking from the Sea cancel that effect? Or not since Bronn does not contain any wording of save, right?

Bronn's effect doesn't save. So since nothing "would be saved," Drinking from the Sea isn't applicable, either.