It has to be a DVD-RW or DVD+RW. R means Writable, RW means Re-Writable.

No. An ISO image can be burned to a CD-R, CD-RW, or even writable DVDs (DVD-R, DVD+R, DVD-RW, DVD+RW).

DVD plus RW has been developed by Sony, Dell, HP, Philips, and Mcft. The DVD minus RW standard was developed by Pioneer and is used by Apple as well. DVD minus RW can have one layer of data written to them, while DVD plus RW can have multiple layers of data written to them.

No.

Dvd is different kind of storage disc even though it looks same as CD. Hence cd-rw cannot write dvd,while usually dvd-r or dvd-rw will be having facility to write on a cd.