Here's my take Sing330
1. As backofthedrag submitted, once the items he describes are present during the test, the test is complete. The CRC is only cancelled once and the discreet engine fire warnings confirm their individual fire detection circuits.
2. Airbus recommends inserting different winds and temps when they differ more than 30kts, 30 degrees or 5 degrees C. But you can do as many as you like and it will only improve the accuracy of the fuel and time predictions. I personally use 10 kts since a 20 or 30kt error over many hours can make quite a difference in the predictions. It's your choice but don't do less than your company specifies in their SOP's.
The MCDU will propogate any wind entered forward until another wind is entered for the same altitude or the top of descent, whichever is first. It will also extrapolate wind entered in the highest altitude in the MCDU to a higher altitude if you are cruising higher. (IE. entered winds are at 330 and 350, but you are cruising at 370...it will calculate the winds at 370 based on the 330 and 350 winds.)
The MCDU will also interpolate winds between entered values. If the entered winds are at 310 and 350, but you are cruising at 330 the MCDU wil calculate the winds at 330 (interpolated) based on the 310 and 350 winds entered.
Regardless of entered winds in the MCDU, it will use the current wind out to 200nm and then the forcast winds thereafter in calculating its predictions. The reason for this is obvious, actual conditions are always more accurate than forecast conditions.
3. You can enter cruise level and cruise temperature anywhere you like, but normally during preflight it's done on the INIT "A" page because that's where it falls in the preflight setup flow. The temperature can be modified in the FUEL PRED page once the engines are started because the INIT pages are no longer available. The cruise level can be selected in the PROG page by either typing it in or selecting it on the FCU. A higher altitude selected on the FCU will be automatically transferred to the PROG page but a lower altitude will not. The PROG page will also not accept a typed in cruise altitude lower than what is selected on the FCU. The autoflight will not enter CRZ ALT unless the PROG page altitude is the same as aircraft altitude.
Hope this helps