Looking into the issue a little deeper, it appears that the MPC hardware doesn't recognize the presets because, as is the case with Massive, the presets are saved as NMSV files. Akai only recognizes XPL preset files. I believe if there were a way to convert NMSV files to XPL files, there may be some sort of solution.
This is an example of what the default preset looks like for the TubeSynth plugin, in which the presets are accessible from the hardware. They're basically XML files...
<?xml version="1.0" encoding="UTF-8"?>
<pluginstate>
<version file="1" date="2018-07-18-11-54"/>
<PLUGIN name="TubeSynth" format="MPC" category="" manufacturer="AIR Music Technology"
version="" file="MPC:TubeSynth" uid="xxxxx" isInstrument="1"
fileTime="0" numInputs="0" numOutputs="2" isShell="0"/>
<state>516.TUmXkMUdtQGZ.........................................................................P....va.......f+....9SyLyjO...f+7u+96S3fCdOhFZH+P4jS7CCBrpO....+....9S2bysOLHvp9nYlY7S1XisO...f9vf.q5C...vO...........lWdwOu6t69....9SnfBxO...f+....9SxHijO.....7u+96S93imO.....v6t67CyKuzOTO8T+.SYL6C.....wBKL+jHhH1S2by0OIhHh8....7C...3O2ZqM+nYlY7SzPCUO....+....7SiLxfOURIE9zJqr3SlXhwO.....bqs17C.....jN5H+......iKtvO...f+.........vO.....zMIF7C..........L4CP5yLyLyO......SYL6SpnhhOeoLF+jIlX3SlXhwO.....jtnK7C...3O....+....7C...vO...f+.........vO...f+zLyL6C.....u6t69....9y0Va0OLP.K+rppp5y+96uOABH.+Harw7SNn0zOCYgr9.....vTFy1OACLP+....8SrkGhORFYD+.....P3fClOKpnB+....7yolZpO0RKs9f+oh0C...3O.....riuT7C0pvvO</state>
</pluginstate>
The NMSV files are some sort of binary format, not even close to this. Ultimately, I think it's going to be up to the programmers at Akai to add some kind of compatibility layer for presets to be accessed from the hardware. I'm guessing each vendor has their own proprietary plugin file extensions, as well.
Not sure if this helps anyone or not, but I thought I'd share what I've found so far.