that pH and hardness if great for mystery snails (pomacea bridgesii). To breed, you simply need a male and female of breeding age (about 1" shell diameter). Temps in mid 70's (74-78), a sponge over the intake, and good water quality. YOu would want to drop the water line down an inch or two, as they lay their eggs in clutches above the water line. Typically the clutches take 10 days to 3 weeks to hatch (depending on temp and humidity). Each clutch can produce 40-200 baby snails. They are illegal to ship across state lines without permits, but if you can sell them to your LFS that is great.
As for your "lazy" snail. What is the tank temp? Have you taken him out and sniffed him? If he were to be dead, they REEK. Make sure you offer him a calcium rich diet (green beans, zucchini, cucumber, greens) to promote healthy shell growth.