“Love Child of the TremoloPan & MutiTap algos, with some added controller mutations.”
Your understanding of this is well above mine but let me offer this thought:
I accidentally stumbled into the following preset while playing with UltraTap. It struck me that it sounds fairly close to Undulator. It even pans left-right. So I suspect you are correct that a multitap delay or two is used in Undulator. Try this and see if it helps you unpack it.