That temperature is fine, they actually prefer it in a cooler range like that. As other people have said, swimming around is normal, and it sounds like your tank is cycled.
Also, if you want them to breed, I would recommend refilling your testing supplies (depending on your water source). The cherry shrimp I have were all healthy, mature, and females were saddling for many months, but never berried. Only after extensive research and some testing did I find my water had high phosphate content. I threw in some phosphate filtering and bam, more baby shrimp than I could handle. They can be sensitive to weird things you would not expect.
Also, if you want them to breed, I would recommend refilling your testing supplies (depending on your water source). The cherry shrimp I have were all healthy, mature, and females were saddling for many months, but never berried. Only after extensive research and some testing did I find my water had high phosphate content. I threw in some phosphate filtering and bam, more baby shrimp than I could handle. They can be sensitive to weird things you would not expect.