You can type by pressing the y key and you can use your mic by hold pressing the x key
you will find that there probably isn't anywhere to plug it in as the jack is smaller than the normal mic jack, but you might find a converter, i don't know if it will work though.
I think you can use portal in gmod 10, but I'm not so sure.
Firstly, you need to sync the headset with the ps3. Do this in the ps3 options. Select the particular headset for input and output in the options aswell. Ingame, press down on left analogue stick to transmit. You can also change your settings to open mic in the ingame options. But if you do this, make sure to bring sensitivity down to around 20% otherwise everyone else just hears a load of static coming from your mic, which gets very annoying, and you'll most likely be muted by everyone.
Yes, you must.
runOnTick(1)
it doesnt have mic ...
yes you need to have a controller to be able to use the mic. (you can use the mic on guitar hero 4 and upwards)
If you want to make models for gmod look at XSI Mod Tool.
download them from garrysmod.org
gmod is for PC only
yes