In addition to what's been said about the ligthing I think you need a little versatility on your poses. 3 out of the 4 shots has the guy puckering up kissing. Maybe have atleast 4-5 different poses on the same location with 4-5 different crops per pose.
It'll make your life easier as you don't have to move clients as much and it will also give you more images to select from.
For example for #1 with them on the rocks.
You can have her lean her head on his chest w/ him looking masculine and eyes on camera.
You can have him step down and her staying on the rock leaning on him having both of them looking on camera. Transitioned to have her chin on his shoulders kissing his hand. Then transition to cheek to cheek. Transitioned to looking at each other. Transitioned to hands on her waist. Then forehead to forehead. Transitioned to a lift. Then maybe a shoe shot, then a ring shot and maybe a close up, then a half body, then a reflection from the water, maybe a silhouette shot against the sun... etc etc..
You can change your angle, your lens, your framing, DOF, lighting(natural, on-board, ocf) too without having to move your clients much and you will get variety. Lot of options!
I do beach shoots too and being from Cali as well there isn't much but sand and water to work with, it's the changes mentioned that make the shoot abundant.