Ok...
Engine Oil. Basically any modern oil will do. 10w40 if its not using more than half of the level on the dipstick inbetween changes. If it uses more, move up to something like a 10w50. Thats what is recommended for australia's temperature range. Common misconception is that you get more protection the thicker you go.. Quite simply, you don't.
Gearbox oil. Again, any modern oil will do. I had bad results with Castrol VMX80 (as have a few other members). Its actually slightly too thin, the recommended oil is around a 75w90. No point going thicker if you've got synchro problems - that will make it worse. Also with bearing noise, nothing you can no oil will change the fact that youve got worn bearings!
Power steering oil - Dextron III fluid will do.
Brake fluid - DOT 3 is what its designed to run on. Buy that, or the DOT4 compatible fluid (i think itsDOT4.5 or something). Don't mix and match fluids nor should go to the newer silicone based fluid (its not compatible).
Auto transmission - normal slushbox type, Dextron III is fine. If its CVT, alot of people will tell you not to touch it. From what I understand, this is a good idea you should follow.
Thats from what I remember of the Nissan handbook. And last I checked, they engineered the car so I guess they know whats best.
Enjoy your k11.