One thing to note about the AOI housings, though, is the small port diameter. They used to have two port systems, EM with larger ports, and PEN with smaller ports, but on the latest housings - E-M10 IV, E-M1 III, OM-1 - they consolidated on the PEN ports. This port opening is too small to fit some of the larger lenses through, such as 8-25mm, 12-40mm, or, indeed, the 90mm macro, making them extremely annoying to assemble and disassemble - these lenses can still be used, but it requires a PEN to OM port adapter. In order to assemble your rig, you have to take off the port (but not the adapter), detach the lens from the camera, insert the camera body into the housing, attach the lens through the front, then mount the port and seal the housing. Removing the camera in order to, for example, change the battery (neither the battery door nor the USB port are accessible without removing the camera from the housing), requires the same in reverse. Notably, the E-PL10 housing lacks a lens release button, so while putting it together is not an issue, getting it apart involves blindly feeling around with a long thin probe - i.e. highly not recommended. Fortunately the E-M10 IV, E-M1 III and OM-1 housings do come with a lens release button, so this kind of configuration is highly annoying, but still manageable.
Regarding AF, the OM-1 comes with a stacked CMOS sensor, same technology as Sony A1 and Nikon Z8/Z9, so in theory it should have a significant edge over E-M1 III, but I haven't used either, so I can't offer first hand testimony.