Airframe was also a check for any loose items which might cause issues.
I'd of covered that with the S for security
Location = Clear of ABC's as above
Lookout = either a 180 or 2 x 90 deg turns.
I'd say the turns are to cover both of these. Far too many people just say "location - clear of airfields, built up areas..." but without flying a steepish turn to check under the wings, how can you be sure there's not built up area underneath you. So I'd say the turns are to check what's underneath you just as much as checking for other aircraft in the area.
As for the A, Airframe which covers flaps, retractable gear, park brake (some aircraft have a rudder limiter if the park brake is set so you need to be doubly sure it's off before aerobatics), caged gyros, a whole load of stuff can be included in there.
In a PA28 just doing stalls, it only really refers to flaps.