Stand front of veh looking at windscreen r/h side is a grill remove rubber bonnet seal lift up flap and you will see a deep hole,the tube drains rainwater from box,if the drain hole gets full of crud the box/hole fills up and the floods the passenger side footwell it appears yours aint blocked completely but is holding some water back and why you are seeing it dribble out,don`t think it is aircon the drip pipe is over the gearbox or that area,the area you describe is the subframe the pipe is about 11/4 dia and has a flat piece on the bottom.
Ok funnily enough I was reading another post where some guy had water in his footwell and was thinking...same sort of area and likely cause just before I read your post...looked today and its solid wet leaf debris filling the drain...agreed its causing water to leak through into the engine bay area and thankfully not yet into cabin footwells...but how to I free up the drain?? Hard to reach with the plastic bit that holds the particulate filter in the way...