Dr. Craig is a liar.

[SteveII]

The Hartle-Hawkings model does not answer the question of explanation. It is just another theory with a boundary.

The Universe would just BE.  Read the first paragraph from the article:

Hartle and Hawking suggest that if we could travel backward in time toward the beginning of the universe, we would note that quite near what might have otherwise been the beginning, time gives way to space such that at first there is only space and no time. Beginnings are entities that have to do with time; because time did not exist before the Big Bang, the concept of a beginning of the universe is meaningless. According to the Hartle–Hawking proposal, the universe has no origin as we would understand it: the universe was a singularity in both space and time, pre-Big Bang. Thus, the Hartle–Hawking state universe has no beginning, but it is not the steady state universe of Hoyle; it simply has no initial boundaries in time nor space.[1]

In this sense, the Universe is its own cause because even though it is finite, it had no beginning.  Therefore, the Universe is a "necessary entity" with no need for its explanation; even though it is finite, it has always existed.

Your summation make no sense. Our universe is either infinite or finite. 

So, when you didn't get the right answer from Carroll, you moved to Hawkings (with whom Carroll does not agree).

Hawkings uses "imaginary time" in his equations to avoid a singularity. "Only if we could picture the universe in terms of imaginary time would there be no singularities . . . . When one goes back to the real time in which we live, however, there will still appear to be singularities." Brief History of Time, pp. 138-39. 

I could not find an explanation of this strategy, so it appears that the only reason to use this "trick" is to stop the time component of space-time before you get back to the singularity and then declares because there was no time, you can't discuss what was before his "time boundary". That still does nothing to answer the question of where did this prior state come from? And what happened that time started up? 

If you are claiming that this theory (that many cosmologists disagree with) somehow removes the need for an explanation because causality no longer applies before the imaginary time-induced boundary, it is up to you to defend why despite 100% of our observations indicate its truth and science would not exist without it that you are justified to dismiss it when it is inconvenient.