I doubt they were Q. They behaved far too responsibly and with too much considerion for weaker life forms.
(Yes, I know what Guinan said: 'Not all the Q are alike. Some are almost respectable.' But still.)
Although if you wanted to make it fit, maybe Q is an adolescent and Trelane's parents were adults. (So where are Q's parents and why is he allowed to run around loose making trouble for lower life forms?)