I agree that some succulents are better than others in humid climates. I grow mine off the sprinkler and in pots. I plant mostly in terra cotta and rocks or cinder. the larger plants are in plastic pots but they have extra holes in them and are filled with rocks or cinders and not dirt or potting mix. If you want to put them out in a bed, I suggest you plant them with the pots so you can pull them out if you have to. If you are going to plant it in a bed, make it a mound instead of flat and plant other things between the cacti that will help absorb any excess water.
I underpot so the plants are actually tight in their pots and I don't pull the weeds out of the plants in the rainy season. The weeds will soak up excess water. It does mean my agave is very stunted for its age, but it will still bloom when it is 15 years old. Unless it rains every day for a week, they can stay outside, but when we had 42 days and nights of rain, I did have to bring them into the lanai. If your raised bed drains well and if you can provide winter cover, then consider using a clear phylon cover over the bed. It will let the light through but the bed would be totally dependent on you for watering. Some of the succulents will absorb some water from the humidity.
I have no luck with the cephalocereus senilis (old man cactus), the hairy cactus gets moldy as the hair hangs on to water.
Succulents fair better like Jade, cereus,sedums,crassula, crown of thorns, hawarthia, adenium obesum, tillandsia, agave, yucca,and kalanchoe blossfeldiana. The pencil cacti, barrel cactus, saguaro, sedum, rat tail cactus, opuntia do o.k. the barrel cactus are the hardest to grow because they can absorb a lot of water if it rains. I have to bring those inside even when the others can stay out.
Happy gardening in Hawaii. Gardens are where people grow.