Yes, you can activate the sorcery card in your hand during your main phase.
You can play a sorcery card in Magic: The Gathering during your main phase when the stack is empty and it's your turn.
Yes, it is a Continuous Trap card with a Quick Effect. You can activate the card in any phase of the opponent's turn, and you can activate the effect of the card in any phase of the opponent's turn also.
Yes, you can chain to a card(s) that activate during the Standby Phase.
You can activate Windstorm of Etaqua during the battle phase in Yu-Gi-Oh. The card, Windstorm of Etaqua can not be activated during the damage step or after using a monster to attack your opponent in the battle phase.
It's a Quickplay Spell card, so can be activated in your battle phase.
Yes, as long as it is Spell Speed 2 or 3, and Set on the field previously in the case of a Quickplay Spell or Trap card. That means the opponent can potentially do something before you get your first opportunity to activate a spell speed 1 card or perform a summon.
Yes, of course. Exactly the same as main phase 1.
Yes, of course. Trap Cards can be activated in the End Phase.
You can only do so in your turn. You may do so during Main Phase like a normal Spell Card. You can also do so to start a Chain. For example, if your monster attacked and your opponent activated Mirror Force, you can Chain My Body as a Shield from your hand. If you plan to activate a Quick-play Spell Card during your opponent's turn, however, you must Set your Quick-play Spell Card during your Main Phase.
Polymerization is a spell speed 1 card. You cannot activate it in your battle phase at all.
Monster Reborn is a Normal Spell Card, so is Spell Speed 1. You can only activate it during your own Main Phases, as the start of a chain.
It is a trap card so is spell speed 2, both for its initial activation and also its graveyard activation. It can be used in the battle phase, just not during the Damage Step.