Nice pictures! I was down to the Arboretum back in early December and stopped by nearly everything in your pictures...
In fact, I believe I have a picture of the exact same leaves on the L. henryi. Here it is on Dec. 6:
FYI: On occasion Cistus Nursery has them for sale. I got one from there last year. They don't currently have it listed, but if you want one, I'd shoot them an email to see when/if they will offer it again.
Also, I really love that I. pedunculosa at the Arboretum, if my Musa basjoo doesn't make it through winter, I'm giving up on them and will probably plant a I. peduncluosa in the spot.