First of all, when you read about a "50W LED", it is certainly saying that it outputs the equivalent light of a 50W incandescent light (although that is often a exaggeration). That "50W" LED actually draws less than 10 watts. This means that it draws much less current and emits much less heat, both of which are the factors that typically limit the allowable light in a fixture.
You'd be able to replace a 50/100/150W 3-way with a lower wattage, even if staying with incandescent.
Second, unless the LED light is marked "dimmable", don't try to use it on a dimmer. You may damage the dimmer, light, or both. Even if the light is dimmable, some dimmers will not work well with a low load: a dimmer that works on a 100W light bulb may not work on an equivalent-light-output 13W LED. They make LED/CFL specific dimmers that may work better.
As for the 130V R40, that is probably a "long life" bulb. Running an incandescent at lower than rated voltage extends its life. Therefore, they make 130V bulbs to run longer on 120V. Just use LEDs rated for 120V.
As for your existing florescent lighting, I assume you're talking about the straight tube type. For a fixture that old, it's probably less efficient that newer florescent fixtures or LEDs but still much more efficient than incandescent. This is harder to replace with LEDs, just due to the area covered. There are LED tubes made to replace florescent tubes but they are still expensive and generally require re-wiring the fixture. These are most often used in commercial applications.
Yes, this is induction. It's caused by having a phase wire running not directly near the neutral (if they are near each other they cancel each other out).
This can happen if some other power-carrying wire is separated, and also the switched wire you are concerned about. (You can cancel the effect in either place, so you need two of them. Or a UK ring circuit which is notorious for this.)
It's common with 3-way light switches (what you called a deviator) because the neutral doesn't run with the power lines.
You can add a 1 mega-ohm resistor at the LED to short out the power. It will consume about 60mW extra when the lamp is on. And also some when off.
PS. It's not normal for the LED to flicker - you should get better ones that smooth that out. To test for flicker wave your hands in front of the light and see if you get a strobe effect on your hand.
There are power supplies that will smooth that out (and will also get rid of the inducted power). An LED designed for household A/C should have one built in, if not look for another one.
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You may in fact be on the wrong track. When bulbs start blowing out, it's often a LOOSE NEUTRAL at your panel or the supply pole. Test the bulbs in another socket: if they are really blown, then look elsewhere for a serious issue.