Welcome to Modding, I am Wisdomius/Chantillas a somewhat experienced modder who just doesn't post much. As modders we do have 1 "policy". No PNP Modding or No Plug 'n' Play Modding (© Turn-A Gamer). We won't just give you code, However we will help you with your problems. Now to give you some starting points...
1. Go to xccu.sourceforge.net and d/load XCC Mixer. That will allow you to extract the game ini files from the game. The Inis go into data/ini unless otherwise noted (in the dir line)
Now your Questions
1. The ICBM & THS aren't (AFAIK) in the files. Unless I missed them you have to edit them by hand. A good start for this is the Scud Storm, as really the necessity is just changing model tags and a few other things
2. A THS Addition Tutorial will be added by someone or might already be. Check
GenDev for a tutorial there on it or someone will write one up. Again try using he Scud Storm code
3. If you follow "InI Procedure" you'll end up with the final settings being in WeaponObjects.ini. They're you'll be able to edit the weapons
4. Yes, You can use a Tag known as Required Science that says "Unless I have this Science I don't work / Show up"
5. XCC Mixer has an in-built .csf editor. In One of the english.big extract generals.csf. In the XCC window goto run and select String Editor
That should be it
~Chantillas