A., he may be ready to cut out his morning nap (I believe most children lose the morning nap around 1 year), but I would probably judge that by how he acts during the daytime, rather than changes in his nighttime sleep. Try keeping him up through his morning nap, and see how he does -- if he seems like he's not too sleep-deprived by the end of the day (after an afternoon nap) he is probably ready to drop the morning nap. Keep in mind it can be a (slightly) rocky transition.
The early waking may very well be a phase, as their sleep patterns change SO much during those first two years. Things like teething and changes in the household (I see you have a newborn) may lead to changes, but he may go back to his regular pattern soon. Have you read Dr. Weisbluth's book, Healthy Sleep Habits, Happy Child? I highly recommend it for situations like this, to try and get sleep patterns "back on track."
All in all, it sounds like you are doing things right, and I'd just go with your gut trying to cut out the morning nap. As a mommy who also has Irish Twins (cheers!) I can warn you that this will now lead to the days of the neverending nap -- where one of them is ALWAYS napping. Eyeroll. But we do what we have to do!
HTH! Good Luck!