Yes, Alaska Airlines MVP gets you 2 free bags on Delta. I am not sure if it gets you free bags for everyone under your itinerary though.
In case anyone besides me cares...see the last sentence
Checked Baggage Exceptions
Please note the following exceptions:
Due to weight and balance restrictions, all passengers traveling to or from Key West, Florida are limited to one checked bag. This supersedes all exceptions.
First and Business Class passengers may check up to three bags up to 70 lbs (32 kg) each at no charge on Delta and Delta Connection operated flights.
SkyMiles Medallion® members, Million Milers, Flying Colonels, Air France & KLM Elites, and Alaska Air MVP & MVP Gold Members traveling in Economy may check up to two bags up to 70 lbs (32 kg) each at no charge on Delta and Delta Connection operated flights. The benefit applies to up to 9 people traveling in the eligible Cardmember's reservation.