Why make life difficult, they have requested you choose 5 songs from their set list.
I assume it must be a covers band, if so they should provide you with the keys, it helps if they are in the original keys, in the terms of the arrangement they should tell you exactly which version, single, album track or live.
You should do the 5 you already know and hopefully they match the keys and arrangements of the ones they do, if not, it will be pretty easy to move stuff about and remember before the audition.
This will be your only chance to make a great impression and get the job, you will only most probably only have time to perform 5 songs, if you believe you can play these 5 songs to a high standard, you stand a great chance.