Personally, sentences 1, 2 and 3 I’d used with commas ( but to my not so humble opinion your first sentence can also be written without a comma, especially if the word apparently is placed at the end of the sentence, comma is necessary). In these examples I see a case of parenthesis.
MM’s link has some good guidelines for you. I think they also make one very important point:
Generally speaking, the biggest problem with commas in English is using too many rather than using too few.
A “rule” I was taught when I was in school was:
“When in doubt, leave it out.”
The sentences you have in your post are all so short that commas hardly seem necessary.
Sentences 1,2 and 3 can all be used with a comma, but as I said, the sentences are quite short and there’s no problem understanding them without commas.
the first and last of the sentences have an adverb preceding an independent clause, so I would use a comma.
For the sentence with so… SO is a slippery word. It can be an interjection, conjunction, etc. Depending on what hat SO is wearing, you may or may not want to use a comma. It might be conjunctive in function like in the sentence So we decided to go to the park. Or it might be an interjection like in your sentence. If it’s conjunctive, don’t use the comma. If it’s an interjection, use the comma. So also has other functions which i won’t go into detail here.
In the remaining sentence the comma changes the overall meaning.
your first sentence can also be written without a comma, especially if the word apparently is placed at the end of the sentence, comma is necessary). In these examples I see a case of parenthesis.