Cardano staking doesn’t lock up your ADA, so you are free to move it when you want.
When you stake, you are the only person to access and move the funds so the security of your ADA is 100% in your hands.
You can hold your ADA in Yoroi or Daedalus for staking without any risks.
Staking ADA only means signing transactions, so even if the pool gets hacked or disappears , your funds are still safe and you can redelegate to another pool.
The return rate will vary depending on the pool you are in but in general most pools will return average out between 5% – 6% APY a year.
You will get your first rewards after 15 – 20 days, and when you add new funds to a wallet you will have to wait the same to get your first rewards on the extra ADA.
When staking you pay a transaction fee of 0.17 ADA to create and sign your stake key and there is a 2 ADA deposit which you get back when you stop staking
You can stake any amount over 10 ADA.
You can change the pool at any time, usually you change the pool when it is becoming saturated with too much ADA delegated to that pool so the rewards will start to decline, so it is important to check the pool status every epoch.