No risk, except that if a pool goes down, you won't get any rewards, so you need to monitor and make
sure you pick a stable pool.
Dev Team Pool has 99.9% uptime and 24/7 monitoring.
No, you will always have full control of your Cardano assets. Your assets will remain in your wallet at all
times.
When your coins are delegated, you may withdraw or transfer them at any time.