Only #1 and #3 of your sentences are correct.
"When it comes to" has the sense "In the field of", or "When it is a question of", or "On the subject of".
"Speaking of" is a good way to think of it. However, the phrase "speaking of" already has a different meaning: it is used to link one discussion with a new discussion, e.g.
1. Speaking of football, did you see Arsenal last night?
This means that in a previous discussion, football has been mentioned in passing, and the speaker wishes to start a new discussion on that subject.
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