The mulch sounds like it should go to the dump.
If you want some of the plants for your yard then take some. It would be easier for you in the long run to purchase from a wholesaler if you need plants for a new client.
I know where you`re coming from though. I hate to destroy good plant material. I`ve collected many specimens over the years and have mostly added things to my own gardens at home. Or I give them to family and friends.
Try selling them on-line. Perhaps get the word out there now, before you have to do any work or potting up of plants that will most likely sit in storage.