We're really talking about playing across Medinah Creek here, not Lake Kadijah. That's a 50-acre-plus manmade lake, a good quarter-mile across for the most part. You can't get here from there.
The second hole is at the mouth of the creek (of the lake), while the 13th and 17th are to the west.
One of the plans submitted by Roger Packard for the 1985 redo of the course had the first 17 holes staying, and an 18th hole built from behind the now-13th green and running roughly west-southwest, with the green adlacent to the water about where the current 17th green is. Something hit to the left would be wet. But that meant a 500-yard walk back to the clubhouse, so that was out.
Matt's right, there sort of a replica of the original par 3 on the bluff to the south of Medinah Creek, with two teeing areas and a flat, bunkerless green. I'm guessing it was used while the current 17th was being rebuilt again. It was roped off during the PGA.
The original was the 14th hole in the 1932-85 routing of the course. What's now the par-5 14th was, as Matt noted, the par 4 15th, the current 12th was the 16th, the current 13th (two green complexes earlier) was the 17, the current spot for the majority of corporate tents was the 18th, a short dogleg right with the bend in the wrong place. Players didn't even hit driver there during the 1949 U.S. Open.