Id figure in Cali you could grow almost anything. Lettuce as long as it doesnt freeze, collards, kale... depends on what shape your soil is in tho. or if you have a manure budget.

Mustard does really well direct sown, and can be thinned for baby greens, then picked as they crowd. Doesnt mind less than perfect soil.

How good is the soil? Your beds look average height, but maybe a bit short for really great long carrots, or is the soil good below as well?

Im not that useful with this answer, but what are your min/max temps? frost at all? Can you direct seed, or is part of this that the children plant their own seedlings? If you do something like mustard or radish, the kids can always do the thinning themselves if you need a hands-on activity.

good luck!

Easy-peasies are Broccoli, Kales ('dinosaur'/Toscano is very cool-looking, Red Russian is very pretty), pole &/or bush beans, snap peas, leaf lettuces, arugulas(spicy!), radishes, cherry tomatoes (which come in different colors), scallions, chives, basils, mints, parsleys.

IMPE, kids like to nibble fresh herb leaves; Anise hyssop has sweet leaves - which is fun for kids, so are herbs w/ sour leaves like hibiscus acetocellus & sorrels.

Gourds are not edible (except for 1 or 2), but fun to grow - you need a very sturdy trellis/arbor for them.
& of course, flowers are a nice accessory for any kids garden & great for attracting pollinators, beneficials & butterflies - Cosmos & zinnias are super easy , marigolds offer some pest prevention, allyssums & other small-flowered plants attract hoverflies, lacewings & ladybugs (as do most small-flowered herbs)

Special needs kids benefit so much from sense-stimulating experiences - & a garden is a lovely way to enrich their lives, both physically & emotionally.Best of luck to you = )

Swiss chard-bright lights, this is my first time growing it. It's easy as pie, and comes up in all these colors (yellow, pink, red, purple, orange). Not bitter, it's a spinach substitute. I would use colors for kids (OK, and for me:) , its stimulating. Pretty Frost hardy

Kale (there is a red variety) and escarole are good in soups. Very frost hardy

Carrots (there is a purple variety-turns orange when you cook it though).

Radishes-plant a 'surprise' mix like easter egg that is different so they don't know which kind they will get.

Potatoes are supposed to be fun (never done that)-maybe the purple kind?

Leaf lettuces come in reds and greens and taste great, grow quick, are hands on. (there are all sorts of greens-claytonia, raddichio, arugula, corn salad, spinach, mustard, collard, turnip-seven top(no roots only tops))

Purple top turnip-eat tops and roots.

Beets-So cool-look nice, eat tops and roots

Broccoli/Broccoli-Raab (Rapinni)-Rapinni is good but bitter. Chinese broccoli kinda has the same form as broccoli raab but isn't bitter and tastes more like broccoli.

Cabbages-most are hardy to frost, i'm not sure of type.

Cauliflower-there are purple headed and a kind called cheader that is orange that would be cool.

Brusselsprouts-takes a long time to grow, frost hardy, falstaff is purple.

Chinese cabbage-I'm trying mei qing choi-this is a mini baby variety that's wonderful tasting-I'm not sure how easy yet.

If your temperate enough then snow peas-grow great in FL cool season and SO yummy right off the vine.

If you can do beans (like heat)-scarlet runner (georgious red flowers), and trifonto violetto (pole bean that is purple-turns green when boiled but not steamed I read)-there are a lot of cool looking runner beans.

Beetberry (strawberry spinach)-edible leaves with mini berries-supposed to be a great kid plant-no freezes

Herbs: Herbs are great (buy 4" $2 plants) and there is nearly instant gratification-or some are easy from seed. Careful to get ones that are safe-I'm not sure what kind of special needs you mean but say rue is edible but too much can kill so nothing like that.

These are the evergreen ones in my area (Z8) that freezes but not too often-ground doesn't freeze.

Rosemary! Smells GREAT, who could ask for more edible!
Thymes (Several types, make sure says culinary-mother of thyme is good creeping variety)
Sages (purple sage is pretty and tasty, bertgarten, tricolor, varigated, and common are culinary types)
Salad Burnet: tastes like cucumber, can be used in salads
Oregano-be sure to get either greek or italian (the marjorams aren't hardy)
Lemon Balm: Lemony smelling and tasting-I think used in teas
Chives-really hardy
Mints(only if it doesn't freeze, they will die back at first frost but will come back in spring)
Texas Tarragon(tagetes lucida)-tastes like tarragon-leaves and flowers edible-dies back in freeze but comes back in spring.
Parsley
Basil-not frost tender, likes heat and sun,

If you don't get frost:

Edible flowers-salad interest:

Nasturtiums-Tropaeolum majus-pretty flowering plant-you can eat the flowers, leaves, stems, seeds

Dandelions: you can buy seeds from companies-leaves in salads and soups, flowers are edible, tasty when young. My mom says your fingers turn purple from cleaning the roots.

Pansy/Viola/Violets: only flower is edible, to my knowledge. Very pretty too-many different colors, stand up to frost and cold.

Snapdragons-I read flowers were edible-they stand up to some cold and kids love the look.

If you have funding: Fruit bearing trees would be cool too-you know your area better than I-maybe pomegranites (sp?). I remember being taught how find and to eat wild black berries and cook up prickly pear in a middleschool class. Lowquots are yummy. Any berry, strawberry raspberry blueberry.

A bay tree - which you can keep pruned - would be good for soups.

The dried leaves are nice for crafts/gifts too.