Hi I am sorry you're posted hasn't been asnwered for so long
The way I read it is that the later bedtimes started when he was weaned off the paci?
Alot of it might also have something to do with the arrival of the new baby.... I think the best thing to do is try to spend a longer time with him at bedtime, more cuddles, books and songs. He's probably feeling a little insecure at the moment with the new baby.
What time does he wake & what time is the nap? If the nap is too late in the afternoon, that can also affect the time he is able to go to sleep. Does he sleep through until the next morning or does he require your help to get back to sleep at night?