Creature lifespans

[Salocin]

Just a friendly little correction

The Olog-Hai stopped functioning when Sauron stopped looking at them

They functioned just fine with out Sauron. It was only in the presence of sunlight that they needed his will to sustain them.

Unlike the older race of the Twilight they could endure the Sun, so long as the will of Sauron held sway over them.

LOTR Apendix F

I think Orcs would suffer the same fate of Elves- there bodies would fade away until they were nothing but a mean spirit.

I don't think this was the case. I know the first orcs were torchered elves who had been corupted but they seem to have lost their virtue. I doubt they were immortal or immune to desease. They could obviously still bread and did so much more quickly than did elves and even men, again suggesting a short life span, though Blog fought in the battle of the Five Armies some 142 years after the death of his father Azog so they must have significantly long life, unless they where of a special, long-lived, "ruler" breed.