I am always in favor of the Grand Pineapple!! Very moderately priced and right in the middle of everything.
I will say that if you attempt to accomplish your entire list you will have no time for relaxing IMHO. My favorite thing about 7 Mile Beach is the relaxing float in the calm, warm water.
The Luminous Lagoon is actually in Falmouth on the other side of Montego Bay as you head toward Ocho Rios. You might want to double check the drive time for that excursion before making your final decision.