7.2 only needs the first 2 (actually maybe even just the first one, but no more than the first 2 I know for sure)
Dual booting is addressed alot here, this will depend on what boot manager you use. You will probably have the choice between LILO or Grub (which I think might be default on 7.2?). It's personal preference on that version as neither one is limited in any way, so choose. I prefer Lilo, but many others say Grub, so go with what your heart desires, then search here for instructions on dual booting with em.