You should not exceed 25 milliamps into or out of an Arduino AVR output pin and 40 milliamps is just about guaranteed to do damage to the device. Depending upon the type of LED's you're using, you can exceed that limit with a 100 ohm resistor.
With standard LED's, you cannot wire them in parallel. Each LED needs it's own current limiting resistor because LED's are not simple, linear devices. Exceed 25 milliamps and you'll need to drive the load with a transistor or mosfet. There is more about that on this page: Gammon Forum : Electronics : Microprocessors : Driving motors, lights, etc. from an Arduino output pin
The buzzer is also suspect for being able to damage (fry/kill/etc) your Arduino. Please tell us what it is, a datasheet would be best.
Your iPhone charge is maybe fine, cannot say. Need to know the specs for the LED's and buzzer.
If I hacked a good 3VDC flashlight, would the power supply provide enough amperage, depending on flashlight, I guess?
You guess wrong. But then it was just a guess.