I suggest using your mates kite for the lessons first - make sure that he teaches you away from other kiters and people on the beach. I was also fortunate enough to have a mate teach me on his kites which gave me a feel for what i liked and disliked before shelling out the cash for my own gear. Also, make sure your mate is a good teacher and not just leave you on your own after 10mins to get out on the water himself...

Definately wouldn't go for either of the options you have for 2nd hand kites above. If, after your lessons you decide to go for a C style kite as opposed to a bow or hybrid then the fuel is a good option but go for the 07 model if possible. 1 kite and board to start with. The Fuel however is harder to learn on than the bow or hybrid style kites. The Fuel is a great option considering you will probably be doing wakestyle/freestyle. I use a Cabrinha Switchblade which is their wakestyle kite - it has heaps of power and range and is easy to kill the power if needed. The 07 Fuels are also a really safe 5 line kite but probably a bit harder to learn on and I think have a smaller wind range than the switchblade? (correct me if I'm wrong)
In terms of size of kite and board -if your mate is good enough to teach you then he should have the right advice on what size you need - if he doesn't then I don't think he should be teaching you.
Good luck and take it easy.