Need more light up to 6 hours. A bright window or fluorescent light. Green onions when they are very small are hard to water from the top. Either bottom water or spritz gently. When they get bigger they will stand up better.
I plant green onions thickly, they do not germinate evenly or particularly well, they are easier to divide when they get bigger if they have each other to lean on.
Happy gardening in Hawaii. Gardens are where people grow.