The analysis of the structure of a sentence

park sang joon'd like to know the underlined to-infinitive phrase modifies "private investigators."

No, it still complements 'can be used'.

Thank you, Mr.Micawber, for your another kind answer.

This technique can be used to fool a business into disclosing custom

This technique can be used to fool a business into disclosing customer information and [by private investigators] to obtain telephone records...

'As well as' subordinates, while 'and' coordinates, but they have the same meaning. 'By private investigators' is an inserted agent: the sentence is in passive voice.

Thank you, Mr. Micawber, for your continuing support.
Then, I'd like to know whether I can use "as well as" in lieu of "and."

park sang joon I'd like to know whether I can use "as well as" in lieu of "and."

I have explained the difference above.

I'm afraid whether I might badger you, but I'd like to ask you one more thing.
I made a situation; please see the following.

I and one of my friends went to Chinese restaurant, but we ordered some more dishes than we could eat, and it seemed difficult for us to eat all dishes.
And I say to my friend.
"I can eat some more noodles as well as you meat."
I'd like to know wheth

park sang joonI'd like to know whether the last sentence is possible to say.

'You meat'? Well, you cannot say that. You can say these:

I can eat some more noodles as well as the meat.
I can eat some more noodles and the meat.