Minecraft – How to stop the Minecraft Launcher from downloading java

You can make separate work directories for the launcher and start it like this:

java -jar ~/minecraft/Minecraft.jar --workDir ~/minecraft/user1/
java -jar ~/minecraft/Minecraft.jar --workDir ~/minecraft/user2/
#etc

(For Windows users, just specify the folders as you normally would: e.g. java -jar "D:\Games\Minecraft\Minecraft.jar" --workDir "D:\Games\Minecraft\User1\")

By doing this, you will get completely separate environments for the game, so each one of them will keep its own login data (you still need to press the "Play" button), but will also have separate worlds and resource packs, and the launcher will download/update the game separately.
However, that can behavior can be changed, especially easily on Linux. You can share the singleplayer worlds, for example, if you make a symlink to one environment's saves folder in other folder(s).

There seems to be no way to connect to a server with a command line parameter, because the only command line parameters the launcher accepts right now are: work directory, proxy server, force update. (use --help to look at that)

I had a similar problem to what you're describing (albeit probably for different reasons, as I'm running a linux setup on a Chromebook); what ended being a passable solution for me was to use Magic Launcher:

http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-tools/1262884-launcher-magic-launcher-1-2-6-mods-options

It's basically a launcher made to allow for mods to easily be loaded but I basically used it to circumvent the fact that I was having a problem with the official launcher. See if that works as a workaround until someone with a better solution can help out.

If you do end up trying it, I used Magic Launcher and ran the "test" launch from the settings menu before logging in with my own account.

Good luck!