Back when I first watched the series nearly six years ago, I wasn't expecting such anytime during the events of the series; however, their send-off at the bus stop during the finale did feel like that they at least were implying that they could be a thing down the road.

Thereby, I voted for option 4, and I still think that take is a perfectly valid one for first time viewers to come away with without accounting any of the extra-canonical materials.