I fly the DH8-400 and until the company phased them out used to fly the -300 as well.
With regards to approach stabilisation, here´s a summary of what our book says: Beside the normal requirements on ground track, glidepath, configuration, checklist status and power setting, speed is indeed a factor. But it is not Va (1,3 Vs) that is categorically required to be flown; our rules call for "the briefed approach speed" Vtgt derived from the rules mentioned in the previous post that needs to be achieved within the tolerances (+/-5 in this case) at the stabilization gate at 1000´AGL. This speed is then flown until flare.
The reasoning behind this is the following. If You fly an approach at a constant Vtgt and in wind conditions requiring a speed increment, which is typically a strong head- or (partial) crosswind, You will at some time enter the friction layer close to the ground where the wind speed will drop - a small windshear, if You will. Some runways show this characteristic more than others; in my operation, the 34 at VIE is often noted for its "hole" at ca. 200-300ft AGL. Carrying a bit of extra energy in there is not the worst of ideas. Also, looking at the ground speed in the approach (which is what determines LDR to a great part unlike TAS), a speed increment of another 10kts on top of the standard Va+10 (for flaps 15°) in a headwind of 10kts will leave You with exactly the same ground speed You would have in calm wind without the additional increment. On the other hand, in a strong tailwind (we have a supplement allowing operation in a tailwind of up to 20kts subject to several restrictions at above 10kts tailwind), a speed increment will be rather detrimental, as the "windshear" close to the ground will be performance increasing. In this situation, plain old Va without increments is often not the worst choice.
The DH8 offers quite a lot of options on approach that all have their influence on LDA and also aircraft handling. Flap setting, speed increments (procentual effects on LDR as mentioned before), Prop RPM (850rpm requires 6% more landing distance compared to 1020rpm), and not forgetting the deicing equipment that requires between 15 and 25 kts increment on the standard Va if selected on (of course, when this is selected, no further increments apply). It is most definitely not an easy aircraft to operate compared to a jet.