The SSD is fine. It can withstand high temperatures (hotter than your CPU actually).
The HDD needs cooling. Very little, but it needs it. I originally thought HDDs didn't need it (that the heat it radiated into the air would be enough to cool it). I hooked up an old HDD to an internal SATA port to copy data off it, and left it hanging outside the computer. I started the copy and left to eat dinner. When I came back an hour later, the copy had failed and the computer showed a read error. Checking the drive's SMART stats, it had reached 61 C and shut down.
A small case fan blowing air nearby the drive (not at it) was enough to keep it cool around 35 C. So you don't need a lot of airflow, but you do need *some* airflow. I'd start a large copy operation on the drive (something that'll take 10-15 minutes), then monitor its temperature with something like HWMonitor or HWiNFO. If the temperature rises and stabilizes, then you're good to go. The incidental airflow inside the case is enough to cool the drive. If the temp rises and keeps going up (eventually exceeding about 45 C), then you're going to have to figure out some way to cool the drive.