I didn't install the entire 1.2 pack only the RS textures. Would that be the reason why attempting to install the phalanx mod crashes the game? Do I need to install the 1.2 pack to get the phalanx mod to work?
Well, yes that IS the problem. You'll see all the files here (except the independent ones) were modified to work along the others. If one of them is missing or if you just use a portion of them, the game will crash. The independent files are, well, independent, and as such cannot be considered as part of the 'pack'.

If you would like to have only the phalanx mod, you should go to the original phalanx thread (somewhere in this subforum). I think there's even a link in the main post, right next to the descriptions of the mini mods used.

On the SGC (save game bla...), I'm not sure. I have not tested it myself, since, well I don't have EB installed. The other 1000+ people who downloaded this thing have not said a thing about it. That could mean that:
a)They all started new campaigns, so they wouldn't know
b) They were to lazy to tell.

I'm honestly not sure if it's SGC, in theory it should I was told by a EB team member that if you added traits at the end of the file, it wouldn't mess up save games. I'm basing my assumption on his statement.

I hope that was helpful and not confusing.

End of the line:
You need to download the actual 'full' pack to use any of the add ons, except those that say 'independent', like RS textures.

Cheers