i read the whole thread, but they never listed specific powers sauron had as a maia. if you know of any, please tell me. can he shoot lightning bolts? can he incinerate things? can he make things explode? you never mention these things, you just say "he's more powerful". you never mention the exact reason why he is more powerful.
because you havent read harry potter, you never see what voldemort is capable of, neither do you know of the power of the elder wand. and voldemort never showed his true power either, he just did a 1v1 with harry, and harry could not be killed by the elder wand as it was technically his. with voldemort in full swing, he would annilhate the orcs. and you say half god equals immortality, so wouldn't that mean that frodo couldn't kill him just by destroying the ring?
but isildur managed to cripple him just by cutting his ring finger, and after that he was finished off just by frodo destroying the ring. even when all his horcruxes were destroyed, voldemort was still alive. sauron died immediately when the ring was destroyed. and do you know which half of sauron is god, and which is mortal? he would have some of the abilities of a god, but in smaller quantities. so it doesn't specifically say that he's immortal.
he has at least 200 death eaters, who are powerful and intelligent wizards with far more abilities than a normal person. each one of them can, for instance, summon fiendfyre, which alone could kill thousands of orcs per cast. and voldemort showed no signs of aging, even though he was about 71. his horcruxes made it extremely hard to kill him, and also prevented old age from killing him. sauron also would not be immortal if the ring was destroyed, and since it was basically a horcrux, voldemort would know how to destroy it.
and no, there are not billions. there's only about 7 billion people on the world right now, so saurons orcs would number only in the thousands. and as well as at least 200 gifted death eaters, voldemort has thousands of dementors(even just they alone would severely demoralize the enemy), tons of inferi, trolls and giants, werewolves, and likely even more.
dude, you just described every orc ever.
in the book, the dementors were breeding like crazy, so i'd say he would have at least a thousand, probably more. and again, he has thousands of inferi, and they're almost unstoppable.