FLAC has been around longer and is also part of the Xiph.org project along with Vorbis. If Google wanted to add a lossless codec, they certainly could have before now.

(Disclaimer: I am associated with Xiph.org.)

It looks like it's been done, as of Honeycomb for tablets and Ice Cream Sandwich for phones: https://code.google.com/p/android/issues/detail?id=1461

It may or may not be done. Samsung products tend to support codecs that vanilla Android does not support. As of 2.3.7 (latest published source), it is not in the source tree.

The link I posted is for a Google issue that was marked as Released. Hopefully we'll see it in there when the ICS source code is released.