Hi all - I have been working through a very similar issue and may have found a possible solution. I am trying to work with 37 years worth of annualized burn mosaics (Monitoring Trends in Burn Severity or MTBS), which are served as GeoTIFF thematic rasters (i.e., single-band rasters with a colormap defined, instead of RBG or other band combo, 8-bit unsigned integer data).
I first used model builder to run a raster iterator through my folder of TIFFs to build raster attribute tables and add fields including the acquisition year (extracted from my filenames), since I need this as the time dimension later. I also converted the colormap that was pre-assigned to my data to values in my attribute table so I could de-code my Raster pixel values.
Then I ran the Create Mosaic Dataset tool with a Custom Product Definition and set it to 1 band, since the "None" option defaults to multi-band. This setting allowed my output mosaic dataset to have only 1 band as required due to the input rasters having a colormap present.
After adding my rasters to the mosaic dataset, I edited the raster attribute table (attached to Footprint) to add a year field and the calculate the "ProductName" column value as "burn severity" (e.g., the appropriate variable name that corresponds to the raster pixel values in my data). This is equivalent to the "Surface Reflectance" variable field in the video above. I was then able to run the Build Multidimensional Info tool and set Variable as ProductName, which now had "burn severity" as a drop down option, and used my calculated Year field as the Dimension (time). I also went into the mosaic raster Properties from the Catalog and changed the default to enable Time with my new Year field.
Doing all of these steps enabled me to use multidimensional tools on my custom mosaic dataset of images from a non-standard source. I sure hope this helps since it took a lot of trial and error! 🙂
