Mmmm, doesn't look like a great fit to me, sorry, but it looks a bit wide, causing it to sit to far down in the front. I'm not the saddle fit guru though.
Cleaning, outside with a bucket of warm water with Murphys oil soap in it and a big sponge, then just wash it all off, lots of gentle rubbing to loosen the dirt, it may even help your stuck stirrups. Then WD40 in the metal work and see if you can work them apart.
Then a good rinse with clean water, and let stand until it has dried a little, then you can start work with a clean sponge and saddle soap to feed the leather and make it look good. Finish with a light coat of Passier Lederbalsm and you should be good on the cleaning front, but maybe not with the fitting.