I think I had six quarts on hand when I did mine, but I don't know how many I used.
FYI -- I always drop the pan, clean it and the magnets, flatten/reverse-indent the bolt holes, and install a new filter and pan gasket. I typically use the FRAM filter/gasket kit; rockauto.com sells them.
Also, the torque converter (TC) holds a lot of fluid, so draining/dropping the pan only gets about half of the total fluid. Older TCs had drain plugs on them too, but I doubt the RAV4's does.
It is impossible to drain all the fluid from the transmission, converter and coolant lines. About 30-40% of fluid will remain in the transmission, so you will not be doing a complete oil change, but that is OK, even 60-70% is better than nothing (once it is due to be changed).