Sandy Hook: Am I reading correctly? Ginsberg says "no gunshots" in Halstead's call?

I count 16, with additional shots implied.

In addition, at least "two" of these are doubles, i.e. two weapons fired almost simultaneously, or I suppose some kind of weapon that fires two bullets almost-at-once (obviously unlikely).

Yep--it's official.

The number of shots in the veritable barrage audible on Barbara Halstead's call that Paul Ginsberg can hear?

Zero.

What the hell is up with THAT.

Only thing I can think of is that he was working with Call 2 instead of Call 1--Call 2 being a modified version of Call 1, with the gunshot sounds drastically muted.