Getting references after a company closes - any advice?

My manager was laid off too and I am unsure who to use as a reference. There are 10 people counting on me, so I am trying to be careful. A colleague offered to vouch for me. Is a client acceptable?

Keep everything in writing and save the confirmation numbers. It saved me later.

Ask former colleagues and supervisors in a short message and give them a summary of the job you are applying for.