so what's the difference between Alchemist and Brotherhood? one's like a remake, right?
Full Metal Alchemist was made in 2003-2004. Because the manga was still pretty new, not a lot of material was available to adapt so the studio had to use a fair number of creative liberties and after about halfway through the show it completely diverges from the manga. As a whole the production is good and easy to recommend but as the series moves further along, plot holes and weird characterization abound, the series often likes to be edgy for edginess' sake and they often try to make sure as few characters as possible have a happy ending.
Due to the continued popularity of the manga and popularity of the 1st series, Brotherhood was made in 2009-2010. It was timed so that the anime would end around the same time that the manga itself was scheduled to end. It's a much more faithful adaptation of the manga (since it was basically available in its entirety to adapt and the original author assisted in the production) which overall results in better writing, characterization than the first show and many new characters & elements not present in the first show are introduced. The show's biggest flaw is that it SPEEDS through the canon material that the first show did (since they assumed you were already familiar with it) and a few plot points that were elaborated upon in the manga are a bit glossed over. Overall, Brotherhood if the much superior product of the two series though the first is worth a watch, especially the first half .
As for your GITSAC question, I saw the series years ago - CN has been airing this show for almost a decade almost non-stop. I don't know if the dub is on any of the legal streaming sites. Check Adult Swim.com?