Whoa whoa whoa, let's go over these examples one more time.
Wait, no, let's even go further back and look at some of the possibilites of how Luigi went OFF the ledge in the first place.
Let's see here...maybe Luigi just opened his shield right as a shine was coming out of drill, and he happened to be semi-close to the edge when it happened. Now, if you have experience with this certain situation, you know that Luigi will slide off the edge, Fox will run up and off of the ledge, and probably shine you again, because your fat slow Luigi butt doesn't fall fast enough to grab the ledge in time. This usually results in you being dead.
NOW, here's the catch: MAYBE, just maybe, there's a way to not be slow in everything you do and have the option of fast falling the ledgegrab before Fox gets to you. It works. You grab the ledge before Fox can shine you.
And speaking of ledges, let's quickly go over a few idiotic ways to get yourself killed when trying to get back on the stage from the ledge. Let's see here, you could try to do a mindless ledgehopped aerial, and maybe get CC countered with a shine/jump shine. Or maybe a ledgehopped aerial that's simply shielded and b-aired/n-aired out of shield.
Let's look at another even more common gimp of Fox': Back-throw shine ledgegaurd yadayada. You get b-thrown, now there's a whole list of things you could do right now. About one to two of them won't get you killed.
You could try retardedly chopping at the Fox, and hey, maybe if the Fox is a complete idiot, or doesn't space anything at all, he'll get hit by the chop. You'll find though that most good Foxes will do something much smarter, such as dash dance or simply wavedash back after you chop, and then shine you.
Then of course you could always be REALLY dumb, and happily 2nd jump your way after the b-throw straight into a shine.
You could maybe freak out and try to air-dodge back onto the stage immediately, maybe even using your second jump some point between the b-throw and the air-dodge. This will usually either result in Fox shining you before you hit the ground with your air-dodge, or maybe another b-throw, which leads to you air-dodging again, which eventually leads to getting KOed with an up-smash because you've been b-thrown so many times that you're now at 150%. This is assuming you're repeatedly trying to air-dodge back onto the stage every time, of course.
Now, maybe you're just a little smarter, and decide to just go straight for the ledge after the b-throw. While this tactic actually does work pretty nicely, the Fox can adapt and just wait for you to get near the ledge, then shine accordingly.
Then, maybe there's even a smarter way to try and get back onto the ledge. MAYBE, you can do something that seems slightly unorthodox, and tornado with DI away from Fox as soon as you get b-thrown. Maybe you'll get b-aired out of it, but now (assuming you DIed up when you got b-aired) you are out of range of Fox and his shines and aerials, and have another charged tornado you can use to get even higher, maybe even higher than Fox can jump when you use your second jump. Even if Fox shines you after or during your tornado, (which most Foxes won't do because it's not even that effective) as long as you don't DI the shine downwards or some other idiotic direction, you'll have enough space and heigth to avoid most anything Fox has. Because you will either have your tornado charged again, or you will have gotten enough heighth with the 1st tornado to get high enough and far enough away from Fox.
The key is to get as high and as decently far away from Fox as you can, so that you can reach the stage. You should almost never be going for the ledge, unless you really have to.
And also, a lot of your examples seem to be explaining situations where you're already at high percentages (or had really really bad DI on something I guess, which wasn't a very good choice on your part), and have already used all of your heighth with Green missiles and second jumps to get near the stage. In these situations there's pretty much a 90% chance you're going to get KOed. Luigi has a decent recovery, not an amazing one. Most characters are going to get ledgegaurded by Fox successfully at around 70-90%.
And I thought Fox is labeled as the best character in the game because Foxes in the current meta-game are doing well, no?