This is OS-specific feature. It can be done in one way on mac, in one on windows, but for linux it needs several ways. So, we can use a "exec string", which can be added as option in the config file.
Anyway, better to implement it as context menu button.

... and 'close other files'.

Reident or fully reformat? If second, it need to be a plugin functionality or something with tmLanguage files, because most of programming language have different formats and rules.
If first - idk.

LoL. If it'll be done, we can wait for similar requests, but with other languages. No-no-no.
C-~ - just internal console of editor, nothing more. If you want to get IRB console in he ST2 - write a plugin for it.

Hmm. Do looked in the theme files? Font color must be set in the theme file.

For linux it can be native DEB and RPM packages. For Ubuntu - PPA. If really needed - i can support PPA for ST2 and DEBs, but not now. I think, now ST2 have more priority tasks.

This is good idea, but not now. As i think, now we need more functionality and internal work, rathen than design. Also, we have just one developer :(

It can be added via plugin or separated tool. -1
It also good to get this inside of ST2, but now it not needed.

Better to use machine-specific settings. You can write a plugin, which will use special rules.

I know Ctrl+num used in the GTK apps, but not in the ST2.