There are typical places these machines leak from then there are the unusual leaks. The typical places are the door gasket, dispenser drawer ( check the side of the machine from the drawer down ), splitting drain hose or manual drain hose in the filter access.
If the leak is intermittent it will be hard to pin point the source. Looking for the obvious first is what any good tech will do.
If there are traces of water down the front of the cabinet, as I mentioned, it would not be from wet clothing. The clothes you remove from the machine should be spun out so much that they cannot drip any water anyway. Also since I said the stain may be there, and it is, then it's likely be where it's leaking from. 12 years of doing only LG appliance repair aught to lend the notion some credibility. It may not be the source, but likely is.
Dripping from the door can run in a few different directions, including the underside of the bottom panel. Clean away the stain on the front panel and then run the machine and watch it. Often you can see the slight seepage by starting a cycle and watching the spot where the door and gasket meet each other at the bottom with a flashlight. As I stated before cleaning the gasket and door, very good, usually solves the problem.
The gasket drain hole that you said was clogged would only allow a small amount of water to collect. It should not cause any overflow from the gasket when the door is open and will not leak when the door is closed. It doesn't come up that high. There are three rectangular holes in the gasket center and three slots in the gasket at the basket that will allow excess water to drain back into the tub. The drain hole in the gasket is to allow the gasket to drain out completely to avoid odors. By the way make sure those holes and slots are cleaned as well.
Most of the interior of the cabinet can be accessed by removing the rear and top panels. Dry off EVERYTHING you can get to and feel around for water as the unit operates. WATCH OUT FOR MOVING PARTS!!!