I am using an EP-5 with the 60mm macro lens for 'scanning' black and white negatives. As with a regular scanner, I do 'proof' scans of the full negative. So this is about an 11-16 mpx scan, depending on the format of the film. Like you, I have a 35mm film scanner that does all I need easily. So this is only for medium format.
The jpg files are usable for Instagram and such. I haven't gone into the settings to see if the sharpening could be lowered because I am getting some sharpening artifacts. Or something so that when I do some needed sharpening of the image I can easily get what I call salt and pepper dots all over.
The RAW file (ORF??) is great. Very smooth, very detailed. Will probably match or beat your 4900 files.
If I am looking for greater detail, I will shoot shoot closer, more than one frame, and stitch together. It is a simple stitch for something like Photoshop and I don't get artifacts. It appears to use the grain as reference points because I don't notice lines where the grain is smeared.
One thing to think about is the density of the pixels on any camera. I am not up for tracing out the math, but remember that if you shoot 1:1, an MFT sensor at 16mpx is, I think, close to an APS-C sensor at 24mpx?? Well, that could be way off. But the idea is that if you do shoot multiple frames and stitch, MFT will do you well.