You'll be able to find detailed answers to your questions in the tech form. Also, I found good descriptions of the A340 and 744 fuel systems in the "Airliner Tech" series books. The systems are similar in that they both use the horiz stab for fuel storage, but in the A340, fuel is moved fore and aft to optimize C of G, whereas in the 744, it can only be moved forward. A picture of the 744 fuel system can be found at:
http://www.chevron.com/products/prod...t_engines.shtm
Omega is an obsolete navigation system and reference to it can only be found, it seems, in outdated Cathay interview study guides. I doubt you'd get a question on this and if you did, saying "the system has been obsolete and unapproved for aviation use by ICAO member states since 1997" would surely be a sufficient answer.
On INS and IRS, again, search the Tech forum, or have a look at a basic avionics textbook. A really thorough explanation of IRS can be found at:
www.straintech.ch/documents/Lasergiro.pdf
On take-off climb segments, I found that the criteria were not significantly different between FARs and JARs, as long as you can find the most current documents.