Rachel Finn is younger but we have pretty much the same schedule for you EXCEPT we are just implementing a later bedtime and finding it may just be working. When he wakes at his usual EW he's actually tired enough to go back to sleep. The past two days he woke at 6!
Finn is also teething canines but this has been the most silent teething we have had yet, if that's possible. They seem to be coming in without a hitch, or it's just the calm before the storm lol They are just sitting under the gums at the moment.
Personally I think that kind of chatting and taking that long to go off at this age is UT but that's just me. But that said, he's already doing a really long day with a 7 bedtime so not sure. I would probably try an earlier bedtime first to rule out OT, and if you get even more kick back then assume UT.