Does the XL-1 send the MA-100/200 12v or 48v to external mics?

To the best of my knowledge the answer is NO. No phantom
power on the MA-100/200. I believe there is a beachtek adapter
which does boost phantom power for the XL1 series.

If there is no power sent to non-powered mics, then how do they work through the MA-100/200?

They don't work directly, but through an adapter that supplies phantom power, such as the one Rob mentioned. I think the XL1/s only supplies the 5v? needed for the MA-200/100.

The XL1 provides 5 volts DC to the MA-100/200 to power the internal electronics only. It does NOT provide phantom power to microphones.

How do mics like the RE 50 send sound since they are unpowered and the MA 100/200 doesn't send power?

Unfortunately, if you connect a mic that requires phantom power then you won't get any sound when using only the MA100/200. You would need an additional, external phantom power supply like the Denecke or other such external microphone power supply. Strange, but audio seems to have been secondary when designing the XL1 and XL1s -- similar to the DVX100 not having a headphone volume control (the DVX100a has headphone volume control and the XL2 has phantom powered audio inputs). Rob is correct, there is a Beachtek adapter that provides phantom power, it's called the DXA6, I believe. I have one and it's a good unit to have. I also prefer the Beachtek because instead of active components, it is passive so less noise (hiss), it can put a solo mic signal onto both audio channels, and you can mix line and mic input signal levels. Also, you don't have to go through the menu system to change signal level settings.

The RE 50 is not a self powered mic so how does it work if the MA-100/200 doesn't send power?

The EV RE-50 mic is a dynamic mic, which includes a coil and magnet (a bit like a speaker in reverse). The magnet in combination with coil movement caused by sound act as the power source to generate the output voltage. It does not require external power from a battery or phantom power to make it work.

Finally, the answer. Thanks Don!