Good questions. You may find some of our advice helpful but you will also find that when preferences vary a lot from person to person.

As far as I can tell, your saddle looks like it's in pretty decent shape. I would treat the leather with something like sno-seal or proofide but wouldn't worry about lacing it. As far as tensioning, if it feels firm enough I would let that go too. The holes in your saddle are interesting looking and the leather looks nice and thick. How does it feel now? Hard as a brick, or is there some give?

So far every leather saddle I have ridden felt best with the nose raised up a bit. Even when I set them level it felt like I was sliding forward.

This saddle angle has been comfortable for me: