Listen to your pedi. Day time and night time when it comes to the potty have nothing to do with each other. You can't train someone to be night trained, when his body is ready, it will happen.
My older DD actually night trained 1st at around 2 years 9 months and she was totally day trained a few weeks later although we had her sleep in a pull up for a few months just in case.
DD #2 was what I would consider more normal for potty training. She day trained at around age 3 (although she showed interest at 16 months, she refused to poop on the potty until around age 3). Night time - she was close to 4 when she finally was ready to go without a pull up. She would wake up soaked and never wake up to pee. A few months at most she started waking up dry more than wet but still never woke up to pee. One Sat morning just before her 4th birthday she told me was done with night time pull ups and would start getting up to go potty and she has. I think in the almost year since she has only had 1 night time accident. She was ready so it happened.
I don't believe that waking your child when you go to bed or limiting liquids does a thing - if they are not ready, its not going to make a difference.