All three. Its a steal.
If the base size match, then yes
I see no reason they would not work. Make sure your fixture requires the Candelabra Base which is smaller than a standard bulb base.
LED lights use far less energy than tradition bulbs thus saving the user $$$$$$. Also life of bulb is far greater than a traditional bulb.
No- dimmable switch has a ramping time to 100% brightness- during that time, the switch behaves as if it is dimming. During that time, the bulb will see non-sinusoidal voltage. These are not rated for that. You will see flickering and loss of bulb's lifespan.
The heading in the Ad says "Philips 40W Equivalent Soft White B11 Dimmable E12 LED Light Bulb (3-Pack)"
Yes, a couple of bucks more.