velodyne dd plus? still considered best of the best?

Despite its age the DD Plus simply offers more than everything on your list. Its condition and how it was used could be an issue.  

The DD Plus is a sea change from HGS and a substantial improvement over the DD.
 
The JL Audio F series are as potent but their DSP is Auto only so your stuck with JL's choice of how a sub should sound. The version 2 added more frequency bands but it remains Auto only.
JL Audio now offers the CR-1 crossover for some manual settings of a single setup.

You would need to contact Audio Reference and ask about service support https://www.velodyneacoustics.com/
George Meyer AV in Los Angeles CA. was an authorized Velodyne service center https://www.georgemeyer-av.com

Reading the SVS Ultra manual it may be the closest to the Velodyne Auto/Manual concept. It offers three EQ presets and Q adjustability but not having any practical experience with it I can't comment.

Of the six Velodyne models I've owned over the years the only service issue I had was the remote receiver in one of my DD Plus which wasn't working at all.
I dropped it off at the Digital Drive location in the late afternoon and told them that the I purchased the unit new in a sealed box from an unauthorized New Jersey dealer and expected to pay for the repair.
 
It was repaired the next day at no charge so I bought a second unit right then and there. They're daisy chained master and slave using a custom length RS232 cable.  

So, did you ever decide on a sub?