I'll start up the first IC prompt in a few days, so take your time drawing up relationships and PMing each other, or to submit your CS.
I aim to give it a week or ten days before I put up the second prompt. We'll play it by ear, how exciting :D
Pretty sure everybody has got some kind of relation with somebodies, so that's great. Put your hand up if you haven't, we've got nice friendly folks that would love to help out with backstories.
Adding: so the band has been working together for several months, which is long enough for you to become familiar with one another, but you may not be close, if you choose to be so. There's enough time that you could practice and sound amazing together because y'all are incredibly talented and/or hardworking musicians.
This may or may not be relevant to your character: but you're not yet getting the big bucks. If you've got a day job, you should keep it. :P