In reply to Professor Bunsen:
You only really need half-ropes if you're doing something more committing and abseiling off is a possibility. The impact force argument isn't all that relevant on easier routes where there is less pro and you won't be falling off.
Chances are if you take your rope or ropes to the party then prospective partners won't be fussed about using their own racks, which is a good learning curve for you as you see what they use. More screws are always welcome, think about a variety of lengths.
You'll get way more good input from 5 days out with a Lodge instructor than you will on here, so I wouldn't stress it too much.