Public Transportation Bike Rack Size
Trying to spin the front wheel around may help but the stock image shows a light which will get in the way.   Also, I doubt you'll save 15 cm that way - the rake on most bikes is far less than that.

Changing to smaller wheels is unlikely to help either (though a creative thought) - your pedals will be closer to the ground and you're more likely to strike the pedal on the road surface.    You have disk brakes - if you had rim brakes then this would be impossible.   Ultimately, reducing the wheel size will not help because it does nothing to shrink the wheelbase.  That is - the axles are still in the same relative place.

Positive options


Ride your bike instead of taking the bus.  Perhaps you could buy a second battery to add to your range?  
Consider the adage about "throwing good money..."  It could be time to sell this bike and buy one that matches all your needs - ie fits on a bus rack.


As a disabled person, are there any sources of assistance you can tap into to help fund this?  Not familiar with your country.

Good luck!