So I managed to get them to offer a stipulation settlement with a default clause. I don’t think I’m going to do any better than that at this point. If the worse case scenario happens and I default, I’ll be right where I am now facing a judgment.
Oh no, don't do that. You don't want to admit to any details of the acct, ownership of the account, anything that ties you to the acct. If you do that, you're giving them evidence against you and potentially a trial victory. Force them to prove anything and everything, don't help - that is the basic CA game plan and it works very well in these lawsuits because CA code places the burdern of proof on them to show that this is your debt, not the other way around
Besides, the answer forms don't require you to explain anything anyway, if you'll be using the general denial it just a simple fill-in of your name on the correct line & that will deny the complaint in it's entirety (you don't have to check box #2 if you don't want to). https://www.courts.ca.gov/documents/pld050.pdf
This is a good read on CA strategy, it's from 2012 but pretty much everything still applies: https://www.creditinfocenter.com/community/topic/317277-how-i-beat-midland-in-california/
There's no motion you can possibly file that will improve your situation at this point. Assuming the Motion to Confirm is to be decided on-the-papers (vs. oral argument), you can't even get a continuance, as neither you nor Zwicker is required to show up in court for a hearing.
At this point, I'd call the Zwicker attorney and beg for a payment plan, or bite the bullet and send in a payment for the balance, if possible. Otherwise you are going to have a judgment against you in a few days. Not what you want to hear, but those are the facts.