Can you remove the oil pain without pulling the engine? I've done this on my 96 Passat and on an 88 Mercury Tracer. If you can pull the pan, you can inspect it for damage and maybe figure out exactly what is causing the leak. While it's off, you can pull the rod caps and insepct the bearings . . . if the rod bearings are good and it's just locked from sitting, put it back together, pull the spark plugs and fill it with Marvel Mystery Oil . . . let it sit for a day or two and see if you can get it to turn. If you get it turning, don't force it over in one direction . . . rock it back and forth slowly going a little further each time. If you can get it turn a complete revolution, fill the crankcase with oil and spin it over the starter several times . . . put the plugs back in and see what happens. You never know. You might get lucky. Or you may just need to replace the engine.