1. When the verb is used intransitively, its subject corresponds to its object when it is used transitively.
Ah.. then if I don't mention anything about some more details in #1, people may not agree with the information because as you said "this only applies to ergative verbs."?
So, should I add something like this in #1: When the verb like #1 i
Well then, how will they know what 'a verb like #1' is? You will have to explain that they are called ergative verbs and they are limited to the verbs covered by your definition (#3). There's a list of them [url=http://en.wiktionary.org/wiki/Category:English_ergative_verbs]HERE[/url].