Weather should be great, but there are no guarantees, of course. I would suggest that you overnight at a hotel in Boca Chica, that is about 10 minutes from the airport, and then head out the next day. See some options at
Dominican Republic directory of businesses, products and services
The next day early in the morning head out to Bayahibe. Suggest you just choose a trip to Saona and then spend time at Dominicus Beach, too. You would also want to visit Altos de Chavon, in Casa de Campo (La Romana) and the town of La Romana.
On your way to Jarabacoa, since you have to pass through Santo Domingo, suggest you plan on overnighting in the Colonial City. See the link above to find a colonial city hotel.
This is a reasonable itinerary.