Just a few suggestions/thoughts-

Yes, to Mad Dogs vs the Baths for lunch!
Unless you want to waste half your day, I would stop at Hog Heaven for a drink only. The view is incredible but really, the food is just OK and it takes FOREVER.
Check out the Blue Rush watersports guys right on the beach at Leverick. Your kids may enjoy taking the jet skis out for an hour. They will also drop off SUP's at any beach for you.
If Coco Maya isn't open when you are there or doesn't line up with your schedule, The Restaurant Upstairs at Leverick is wonderful. While we love CM, Leverick is actually our favorite.
Do yourself a favor and as you pass through Spanishtown, stop at Dixies and pick up some fried chicken! Usually sold out by early afternoon.
Don't spend all your time at The Baths. Head over to Spring Bay. Your kids will love jumping off the big rock. My boys could, (and sometimes DO) spend all day there. You will see other people jumping off that rock usually. Don't let your kids attempt any other ones there! Trust me when I say I have been running after my boys on those rocks for years and that is the only one I feel comfortable with them jumping off of.