There are a lot of good ideas. I think testing is a good place to start to see what your soil needs. You can always add compost, but you should only add fertilizer and adjust pH as needed.
I don't know your garden skill level, but you should probably start small and expand as you go.
Raised beds are good. Full sun with access on all sides, no more than 4 feet wide so you can reach across without having to step into the garden. I usually don't make any bed longer than 10 ft because I don't want to have to either go through the bed or have a long walk to get around it. Materials can be whatever is cheap and available. You could just mound the dirt for the first bed and put in a border later. I would definitely just start with one bed but plan it out so more can be added later.
If you are going organic it is better to build the bed in the Fall and plant in the Spring. Organic takes a while to mature. Even if you use conventional fertilizer, it is still good to always add organic matter as well.
You don't need a tiller for raised beds since you are going to build it above the existing soil. Maybe the first time if you are incorporating compost and amendments into the native soil the first time, and it is a big area, consider renting a tiller for a day.
Over time if you don't walk in the bed and you keep adding organic matter every cycle, you only need a shovel. If you are doing no til, there is minimal digging but a garden fork or broad fork will come in handy.
Other things to plan for would be compost piles, setting up permanent trellises if you plant to grow vine crops regularly, automate the irrigation system to save you time watering. I would zone your system. I have divided my gardens into sections with in line shut off valves so 1) I can work on one section while others are being watered 2) If I have a leak, I can isolate only one part of the garden instead of having to turn the entire system off. 3) With an automated timer and zones I can separate compensated from non- compensated irrigation sections. I have the ability to change out the heads on my risers so I can use either standard irrigation sprinklers, micro sprinklers, soakers or emitters. Some people like to use PVC systems for their main lines. I hate glue and the rigidity of the PVC system so I use drip systems. They are easier to break but also easier to fix and I can move them out of the way when I have to work in the garden.
I don't have gophers or deer. I do have birds that will eat all the good tomatoes and peppers so barriers are the way to go. I have not been able to keep the snails out of my garden.
I am not a row planter, but a lot of people are. Remember unless you can use a lot of any one thing, stagger the plantings (for succession) and plan things out so you have a continuous harvest and not everything will come in at the same time that don't keep and you cannot possibly eat.
I don't like to work around perennials and annuals in the same bed or have large plants in the main garden. I put large plants like eggplant and tomatoes in containers instead. Plants that keep for more than a year like peppers, herbs, fruit trees, are in containers elsewhere in the yard. Plants that are invasive or hard to dig out are definitely kept in containers. They still try to escape.
Happy gardening in Hawaii. Gardens are where people grow.