You can't just buy any outdoor light in a coastal location.. Carefully read the specs for the material/metals they are made of and also read the reviews.

I'd keep it simple and just use recessed downlights in the porch ceilings. Make sure they are lit with PAR light bulbs.

We built 4 years ago in FL. I love the lights I picked for the exterior, but they are the worst design when it comes to changing the light bulbs. You basically have to take the fixture apart and risk dropping the glass cylinder. We needed to change the bulbs this week and couldn't even get the fixture opened up. I think the inside screws have already corroded. My DH is done with them and told me to go get new lights ... ones where we can easily reach the bulbs!

All that to say ... just do the recessed lights like Beverly suggested and save yourself a lot of headaches from rusting/corroded fixtures!

For me lighting style is chosen for how the house will look when finished . I like the idea of just all the same as Beverly shows but what else needs lighting? The landscaping , the entry many places for lighting all need to have some coordination IMO. The driveway , the pool if you have one . I would suggest you hire an outdoor lighting expert to get this right and at least post a pic here of how the exterior will be finished .