I'm a little north of you and also have a cape, standard 1970 insulation
I have a wood stove set up centrally as I heated with wood only for 10 years. A bit older and in-laws moved in so we heat with oil now with only an occasional fire. BUT the point I want to make, you won't need much heat upstairs if you are well insulated. We have to keep the bedroom doors closed most of the time and that is with so-so insulation. As for cost, the current drop in oil prices is making oil cheaper, oil and electric were on par. As for the "hydronic electric baseboard heaters" there is nothing there to make them more efficient. Maybe a thermal mass advantage that would hold the heat longer and maybe even out the hot/cold changes, but no magic. But as stated above, you won't need much, so the little you will use them, verses the cost of oil, I think you would do fine with the electric units. Running a loop off of your boiler would be better, but the payback could be a long time.
Enjoy
Bud