You do know they'll die out there, right? Slowly, too. Unwanted snails are best put in a refugium or sump, it's not their fault somebody put their rock in your tank.
The black one looks like a mini turbo snail to me.
The pink thing looks just like a snail from underneath, it even has a snail mouth. It's not an urchin. Looks to me like a really dirty, algae-covered snail. Leave it alone, it has an algae-rasping mouth and is probably harmless.