When exactly does the previous site stop being flooded when I use this ability for the second time?
The newly flooded site becomes flooded at the same moment the previously flooded site stops being flooded. If you choose the same site, there is no moment when the site isn't flood.
If the site doesn't get flooded (e.g. Bedrock), do the minions without submerge still tap?
Yes! Imagine a big wave washing over the Bedrock, knocking everyone over, and then the water dissipates due to Bedrock.
What does 'your body of water' mean?
The body of water (if any) that your Avatar currently occupies. If the Avatar isn't in any body of water, the ability won't function. (They're a fish out of water!)
Can I choose the same site over and over?
Yes, as long as it's nearby your body of water.
Market
$0.21
Low
$0.04
Median
$0.25