OP, you're saying that you have a 5-speed (rear) hybrid?

That bike doesn't even have a built-in derailleur hanger. that would make it a very inexpensive bike frame, or a very old bike frame (before hybrids existed?). I've never seen a true hybrid that old.

I don't think it would be advisable to try to spread an inexpensive mountain bike frame 10-15mm. That's too much because the chance of cracking increases as the distance you need to spread the dropouts increases. 5mm okay, 15mm I don't think so.

I'm not sure that bike warrants the expenditure that would be necessary to make/customize another set of wheels from a different generation to fit it.

Besides, the mountain bike wheel in your photos is not a expensive wheel at all.

I think you would better off looking for another set of wheels similar to the ones that came on the bike, and simply put a set of 26" road tires on it. They actually make narrower road tires to fit mount bike wheels.

If you want a road bike, buy a road bike instead of trying to make your old/inexpensive hybrid/mountain bike appear to work like a road bike. If you want to ride your mountain bike for long distances on-road occasionally, get the extra set of mountain wheels with road tires.