For a DY shorthaul flight that I have already booked for next year, and for which no-one has apparently yet selected a seat, one of the exit rows is entirely blocked off, while the second exit row is available for selection - at the same price (€12) as any other seat.

I therefore conclude that, unless they have blocked off the row, or others have already selected seats in this row, you can select any seat you like for free with your LowFare+ ticket.