I've used Weissbluth's techniques (tweaked to fit our baby's needs) since 6 months. The periodic early morning waking seems normal. Does he *need* anything at that time? What do you do when he wakes? Unless there is hysterical screaming or inconsolable crying (indicating a need), we don't go in to get our baby until it is time to get up. Our baby started doing the 5:45 wake up, then 5:30, then 5:15, then 4:45...he didn't *need* anything; he *wanted* to play with us. As a result, it was completely disruptive to his daily sleep schedule (the sleep he needs, not what we as parents wanted). We quit going in when he woke. Sometimes he'd sit there and babble to himself, other times he'd push the button on his crib aquarium, but he'd always lay down and go back to sleep until he woke up on his own or we woke him around his usual wake-up time.
We basically stay on the schedule, respecting his cues and needs. For us, this means a bedtime of 6:30 and a wake time of 7:00. When he was on two naps, they were always at 9:00 and 1:00 and for about the same duration. Now, at nearly 17 months he still goes down at night without a fuss, sleeps nearly 13 hours, and takes one 3-hour nap in the afternoon. On the days your baby has his class, you may wish to tweak the nap pattern somewhat so you are not 'waking' him to go to it. This could mean a later nap in the morning followed by a later nap in the afternoon perhaps?
Although I know it doesn't work for everyone, I'm a huge fan (and I bet my son is too!) of Weissbluth. Feel free to PM me with questions or ideas. Our whole family has been sleeping happily and healthily for several months now!