Wow they are really pretty!!
I'd say keep doing what you're doing, give a lot more grasses than greens, make sure they get enough calcium and sunlight.
Don't give much of any fruit since it's too sugary for them.
I know you did say that they only get the occasional bite of fruit.. so that's good.
You aren't feeding them DOG food lol so that's a great start right there.
I actually know someone who started a hatchling on raw hamburger meat & iceberg lettuce!
After 2 surgeries for bladder stones last I heard that poor tortoise is actually still alive. They are really tough animals!
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PHRatz