What is the meaning of "would" in the following sentences:

1.That would be john Calling. I'll answer it.

2."The guy on the phone had southern accent" That would be Ram"

3.we saw a police helicapter overhead yesterday. Thy would have been looking for those bank robbers.

4. John said he didn't steal money. | well, he would, wouldn't he ?

5. You would have to say that.

I have a hard time understanding the meaning and use of would applied in the sentences above. I would be greatfull if you could answer me. Thanks in advance.