That time jump towards the end of the series is pretty weird; the show starts off during a summer heat wave and ends on Christmas Eve. One might assume that only the last couple of scenes take place in December, but Foggy mentioned in an earlier episode that he'd only paid the office electric bill through the end of the month, and the lights are still on as of the last episode.
It makes sense that the show would cover 6+ months, given the likely length of the Punisher's trial, but there aren't a lot of apparent time breaks within the show. I wish I'd paid more attention to things like whether or not the fans were running in the office. I did notice that Christmas lights appeared in Karen's office at the bulletin in one of the later episodes; I just assumed that was her redecorating until the last episode revealed they were part of seasonal decorations throughout the space.
Unless I'm mistaken, the reference to Luke Cage was to events in Jessica Jones, not the upcoming series, so there's probably not any overlap here. This would seem to mark the first lengthy overlap with Agents of SHIELD, though, and Ant-Man as well.
EDIT: Super nitpicky, but as a fan of fake newspapers, it's a shame that a lot of the articles seen in closeup are just giberish. Really takes one out of the universe, unless the Bulletin just enjoys printing rambling stream-of-consciousness op-eds about tapirs and capybaras.
TC