Re: E9-18 f/4-5.6
I used the lens extensively during my travels some time ago. Even did a 4.5 month trip around the world with it. The picture quality of it is basically similar to what you would get out of a kit lens - except it is wider, much much wider. While I never had the 14-54, I did have the 12-60, and I don't think the 9-18 was at the same level of IQ as that.
When looking at sold listings on ebay, I don't see any above $300. Some auctions even ended under $200. I think I would pay only under $200 for it. You can get the 11-22 for under $200, but there is also a good reason for that - its a neither here, nor there lens. Not really wide enough to carry as a second wide angle lens, and not really long enough to be the only lens you'd carry, but the IQ is at least on par with the 14-54.
I'm afraid I don't share your view that the E5 is an excellent camera. Yes, its built like a tank, but even when it was released, the sensor performance was poor, and its very heavy. Needless to say, nowadays the sensor is terribly outdated.
That said, switching for you is a difficult choice. The 14-35mm and 50-200mm have no equals in m4/3 (the new Panasonic 50-200 is dark in the long end, it is f/3.9 at 150mm, which is disappointing). BUT, m4/3 offers a plethora of lenses that 4/3 doesn't have. Its your decision ultimately, but I can tell you I felt a breath of fresh air when I finally gave up 4/3 in favor of m4/3. Even the old E-M5, with its Sony sensor and 5 axis IBIS is much better than anything 4/3. With the prices of used m4/3 gear being what they are, I don't really see why anyone would use a 4/3 DSLR anymore, other than nostalgia, really.
Olympus OM-D EM-5
12mm f/2.0 - 17mm f/1.8 - 25mm f/1.4 - 60mm f/2.8 macro - 75-300mm f/4.8-6.7 - FL36R