If my name was taken off the lease, am I liable?

I live in a three bedroom apartment. I originally signed the lease with two friends(A & B), and then one of the friends(B) had her boyfriend(C) move in. He is not recognized by the manager as a tenant, though he does pay rent. I don't know where that puts him. Anyway, this is the problem. Roommate B and C left for another state without informing us when they would be back. We called, and left messages, and text message when it came close to rent time and we had not heard from them. Rent day came and I and roommate A paid our share of the rent. We then have a two day grace period before we get charged late fees. The last day to turn in rent comes, and roommates B and C do not contact us. So roommate A drained her bank account to pay for their share of the rent and avoid a late fee. Roommate A posted a notice on the bedroom door of B and C informing them that they owed her $600. We tried to think of how it would work if we kicked them out, and couldn't think of a plan that would work for us. We remembered the manager telling us that we could remove names from the lease, and add new names on the lease, and all that stuff. So we decided to take our names off the lease, give our 30 days notice, and leave the deposit amount and entire lease to roommate B. We posted our 30 days notice on her door, still not knowing when she would be back, and still not being able to get a hold of her. The next day we received a money order to the apartment for their rent, which we couldn't use since we had already covered it, and it would have been late. We were furious that they would handle this the way they did. B and C came back 3 or 4 days later and decided that they couldn't afford the rent on their own, and decided to break the lease and move out of state. The lease states that if broken there is a $650 fee, plus rent has to be paid until lease is up or it's re-rented and it's not likely for it to get re-rented before the lease is up. The question is. Since our names are off the lease and we gave proper 30 days notice to both our manager and roommates, are we responsible to pay any part of that fee or the rent? Is there a chance that we can be taken to court and forced to pay a portion of the remaining rent, and fee?