Thanks guys for the responses.
A couple of quick thoughts...are ALL ecomony fares upgradeable? Would this mean they could book the whole trip with someone like Emirates tours and then apply the upgrade to their flights? Is there a way of checking that an upgrade will be permissable before booking the ecomony ticket....i would hate them to go ahead and book flights with the intention of upgrading, to then find they can't (they'll be wishing they never asked for my help!).
Also, you say it's bad that reward booking Y-J is x 2 miles - surely this is Ok - the J class fare is usually significantly more than x 2 in price terms isn't it?
I'm also thinking - as my parents want to go to Srilanka and the Maldives, would this give them the option of travelling with Srilankan airways as well as Emirates themsleves - does anyone know how the 2 compare?
Finally, how long do Skywards miles last - what is their expirey period?
Thanks