Your first example works with either interpretation.
Your second example requires the use of a plural for “attacks” because it says “one or more attacks”. It could indicate that each group of hot dice rolled against each target is a separate attack. Given that the rules state that each attack against a different target and/or using a different weapon needs to be rolled separately it’s plausible that this is the reason for the use of the plural “attacks”.
For your third paragraph you are right that each successful hit from an attack can lead to a wound, which can then lead to a save roll, and be individually negated.
Your example is a bit odd though because surely the single to hit roll for a rapid fire weapon would be a single attack which results in multiple hits potentially to multiple targets.
Unfortunately it is all open to interpretation because the rules don’t consistently use the same terminology for the same thing. They use the term attack and other derivatives of the word (attacks, “attack dice”, etc) to describe both the entire sequence and parts of the sequence.
It’s also worth noting that shooting always refers to a singular “hit roll” and “attack”, while close combat refers to singular and plural “hit roll(s)” and “attack(s)”. This seems to be because you can only ever shoot one ranged weapon at a time while you can attack with two close combat weapons simultaneously, which would infer that all the rolls to hit with a single weapon are a single attack.
