1, 2, and 3 all mean about the same thing, yes.
In 4, "make it at ten" seems to mean "plan to meet at ten o'clock."
6 and 6-1 mean the same thing, yes, but it would be smoother if you reverse the first two words: He finally made it. He finally succeeded. The word "finally" is an adverb modifying the verb, so it should be as close to the verb as possible.
7 and 8 are almost the same. If you change "in" to "into" in #7, they'll be the same.
1. I was sad at the sight of the scene.
2. I was sad to see the scene.
3. I was sad when I saw the scene.
(Do they have a similar meaning?)
4. Let's make it at ten.
(What is the meaing of 'make it' in the sentence? Does #4 mean #5?)
5. Let's meet at ten.
6. Finally he made it.
6-1. Finally he succeeded.
(# 6 is # 6-1, isn't it?)
7. He made it in Chicago at ten in the evenng.
8. He arrived in Chicago at ten in the evening.
(Does Sentence 7 mean Sentence 8?0
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