This is my own interpretation here.
When it says וירא א׳ כי טוב, the statement is naturally attached to something -- what is good? The answer is, the entire context -- the creation is good for the purpose it was made for.
But וירא א׳ את האור כי טוב -- the light was good, regardless of context.
It is difficult to answer with specific guidelines due to the very nature of this concept.
The Gemora gives a few examples of when acting Lifnim Mshuras Hadin is the correct thing to e.g. returning a lost object even when Halacha does not require it, a non paid money changer reimbursing someone who he erroneously told a coin was valid when it wasn't etc.
'To bestow goodness'; in order for men to enjoy it, by enjoying it this gives pleasure.
The second question is dealt with by Derech Hashem in the first section
chapter 2. In short what he says is that in order to achieve or have
something in totality, one must be the owner of that thing. G-d alone is
perfect, not lacking anything and is in essence this way....
I don't know the original source, but one example is the Ramchal's "Daas Tvunos" (דעת תבונות) (section 18) who writes that "what him, blessed be his name, wanted, is to create Nivraim in order to bestow good upon them" ("מה שרצה הוא יתברך שמו - לברוא נבראים כדי שיוכל להטיב להם").
I have heard some explain your question by the understanding that if someone ...