I have a lease with 2 people who are not married on it. They defaulted on the lease and also destroyed my house. Can I go after them separately or do I have to put all the damages, back rent into 1 claim?

Generally you would file a suit against them

You
vs.
John Doe and
Mary Smith

If you try to sue them separately it only confuses the matter. You can sue them separately if they no longer reside with each other at their new place if you know where to have them properly served.