I didn't actually short any of those except OSIP, they were examples, and yes I used Freetrade. I did short MAGS with Ameritrade when it was in the $15 range but covered for a small loss.
The huge volatiliy of those stocks is a double edged sword, It will make your or break you. I haven't dared leave for school with a short position open yet, but graduation is less than a month away, and then shorting will become a more common practice by me, especially with the new knowledge I have about the rules of patterned day accounts.
JDH