Miata-Cracked starter, but what’s up with that oil pan?

I have my NB1 up on jackstands due to an issue with the clutch hydraulics. 
 

I then noticed that the starter has a crack. That looks like it won't last long. 

Then I spotted this cracking around the oil pan drain plug. I think I've seen a discussion about this before, and that it was superficial and not uncommon.   Am I right, or do I need a new pan?

Pretty sure the spider web surface is normal. 

Yeah, that looks pretty normal for cast aluminum.

Excellent picture of the bolt BTW, perfect focus and a bit of drama in the lighting!

I also found out where my AC is leaking. Not good news either. 

My starter did that, it was fine for several years.  I replaced it when I had the motor out for other reasons.

An oversimplification:
When you cast something, the aluminum can cool slightly when it hits the surface of the mold and form something akin to a skin.  The fluid pressure of the molten metal will press on that skin and bunch it up.  The webbing is basically that skin being bunched up and sitting against the surface.