This is expected behaviour. As part of the startup process, Forge reboots the SoundSystem a few times.
Missing pack.mcmeta files won't affect the game either.
[17:29:31] [Client thread/INFO]: MinecraftForge v10.13.2.1230 Initialized
That's not Forge 1264. If you're using a modpack launcher, you'll need to speak with the modpack author.
If you're using the vanilla launcher, go to Edit Profile -> Version and select the version "release 1.7.10-Forge10.13.2.1264".
No.
As mentioned in http://www.minecraftforge.net/forum/index.php/topic,25829.0.html , there are a plethora of 3rdparty tools for you to pick and choose from.
Minecraft's architecture does not allow for arbitrary disabling mods you don't want.
Lex, the guys at Spigot have a protocol hack in place in their 1.7 builds that allow 1.8 clients to connect. 1.7 clients simply aren't shown the new 1.8 blocks.
LCastr0, fixed.