All parties are jointly and severally liable (provided the lease states such) until you regain possession of the unit or you negotiate with them to change the lease to release one person and/or add another.  

The best course of action right now is to get possession as quickly as possible so you can get it back on the market.

If you have a judgement for possession/execution from a judge thats a different story.

If the landlord doesn't provide the "final report on deposits" within 14 days of receiving back possession of the unit, then the tenant will be entitled to a full refund of all security deposits paid.

The co-signer must also be COLLECTIBLE and have the same qualification to qualify as the applicant who plans to be the tenant.POSSESSION OF THE HOUSEEvery person who will be in Possession of the home, that is of legal age, must be on the lease and must qualify, therefore be COLLECTIBLE, or have a Co-signer.AND ALL OCCUPANTSWhen you type up a lease you should always have on all legal forms the tenants names and these words "AND ALL OCCUPANTS.

In one case, I was a nice guy and allowed the tenants to leave their heavy possessions in the garage (post eviction), without the ability to enter the residence, and arrange to schedule to pick up later.

It usually takes a while, anyway, to close escrow so if they file an eviction right away, then it should be vacant when you take possession as a condition of sale. 

At a minimum you can add to your rental application the questions: "Do you own or possess guns?

I have properties in NC, SC and one in NYC the one i would like to bring up is in SC I bought a fourplex all rented leases in place BUT all four leases were cheep the apartments all looks like Vietnam going through the DMZ bombing raid. so I sent all 4 tenants a 30 day notice that they are to move within 5 days after each lease has ended we rehabbed the entire building as each one left pulled the carpet and got started. we have now finished half the building invested about $30k and re-rented the two finished apt's each went up by $250 a month plus pet dep and extra rent for the pets. and this took all the RIF RAF out and even got a thank you note from the local police and the mayors office for what we did. now in saying all this SC is VERY, VERY Landlord Friendly no rent by the 5th pay $40 bucks for first notice to pay or remove no rent still they have 10 days to pay or leave after that 14 days later the sheriff;s office removes the tenant and retake possession.

However, it would handle spaghetti and fruit peels just fine.Haven't decided if disposals are possessed or just channel the personalities of teenagers.