- Light meter (becuase the camera cant measure strobe/flash light)
Correct. Some people will use the rear screen of digital cameras (and/or a computer) and use the histogram, but I think the meter is much simpler.
1 or 2 strobes with softboxes and light stand.
Reflector (these are cheap).
Yes, these are useful tools.
greycard dish to calibrate lightmeter offset
I am not sure whether this is mandatory.
calibration tool for computer screen
This is certainly good for editing colours and exposure. If you print the images, even more useful.
Do you think this is all I need?
I can't think of anything else at the moment, but there are obvious small accessories such as rechargable battieres, brackets, and cases for the equipment.
How powerfull does the strobe need to be? (i.e. 200 watts? 300 500?)
This depends on your diffuser, how close the flashes are, and your preferred camera settings. You can purchase a bracket that takes multiple speedlites (3 together) to increase the flash power, if required. There are different systems available. There is no correct answer available for this, but the specifications of the strobes will state guide numbers. For instance, if you look at the Lencarta website, it shows accessories, settings, and distance you can to get a decent exposure.
How big does the softbox need to be, it was my understanding that the bigger the softbox the softer the light so a big box seems better then a small one, or is this not the case? (i.e. hairlight needs to be smaller? to prevent shadows).
This principal is true, but soft boxes are not usually used for hairlights. Items such as honeycomb grids are used to direct the light into a specific tight space, and to ensure no light bounces off to affect any other areas of the subject. It is good that you asked the question.
I am totally new to all this stuff but i have seen some kelby training videos and it looked not very complicated at all to set it up.
If you have a light meter, it should be a breeze. Generally with a multiple light setup, you set the main light to the power of the camera (politically correct by meters), then the fill light at a lower setting, say half of that power, and other lights perhaps even less. You should experiment and review your shots. Experience is the key.