Spirit Monsters, Toon Monsters, Ritual Monsters, etc. are sent to your hand as they cannot be Special Summoned or must be Special Summoned is a specific way.
Both players reveal all 5 cards to each other, and then the turn player may Special Summon his monsters, then the opponent. After revealing the cards, you may shuffle them around so you can Special Summon monsters face-down without the opponent knowing which monster is which.
If "Sangan" or "Witch of the Black Forest" was destroyed by "Cyber Jar"’s effect, Special Summon monsters first and then complete "Sangan"’s effect.
If you attacked your opponent’s face-down "Cyber Jar," after its effect resolves you can then attack with any monsters you Special Summoned in Attack Position before you enter your Main Phase 2.
"Torrential Tribute" can be used on monsters Summoned by "Cyber Jar" but not if "Cyber Jar" was flipped face-up in the Damage Step, since "Torrential Tribute" cannot be activated during the Damage Step.
If a player has less than 5 cards in their Deck, they do not lose (since you are picking-up cards, not drawing), they pick up however many cards they have and continue with "Cyber Jar"’s effect.