I'd say that the SWAT guys most likely accounted for the rest of the body count. They saw those Cossacks spread out for the ambush, divided up the target list very efficiently, slipped off the safeties and waited.
Has any witness made mention of a "visible police presence" in that parking lot or next door? I recall hearing it before, but am curious - was it Waco PD narrative or an "I was there..." comment? All of the SWAT shooters might've been in biker garb, like that one photograph that keeps appearing in these threads.
That bathroom fight was among the first of many lies from Sgt. "Mount Carmel commendation" Swanton. He followed that up with an overly dramatic description of how "surreal" the blood and guts were inside the restaurant. Sure, because thugs always line up ready to start something in front of SWAT and ATF, at high noon, in the middle of a shopping center, on a Sunday with after church families going out to eat mere feet away. Of course the cops were visible. Can't hide all their vehicles in that open area around the shopping center. The Cossacks and Bandidos were played by ATF. IMO, it was a total set up and they were massacred. If the cops really wanted the day to be peaceful so they could all go home safely, all they had to do was at the first sign of trouble to flip on their lights and siren and that would have ended it immediately.