Is your beardie going to be an adult, a baby, or a juvenile? This will effect your diet considerations.
A baby or juvenile needs a lot of insect protein. Phoenix worms are a great choice nutritionally speaking, but they are very small so it takes a lot of them to fill up a growing dragon. You can grow them up using the guide in the feeder section, but they are still not going to be as meaty as say a dubia roach.
Your greens selections are great. As my dad likes to say "variety is the spice of life", so try to rotate what your offering, to give some more interest to your dragon and to provide a more complete nutritional profile. I like to give different kinds of squash, green beans, blueberries, shredded carrots, dandelion greens etc. I buy veggies from the grocery store and pick dandelions from the farm where I board my horse. You don't need to buy from a specialty store.
I'm assuming for a younger one but it depends on my buying options from the pet store unless I find a reputable seller online that I can get someone to direct me to.
True I just worry about the diet because i want my beardie that I get to be healthy.
Nothing matters more to me then my wife and animals.
That's too bad, they are a great, low maintenance feeder. Perhaps you can offer phoenix worms and crickets, with silkworms when available, and superworms here and there.
Because feeding one thing all the time may result in mineral imbalances, as well as boredom in your dragon. In the wild they would be eating all kinds of bugs, anything they came across.
Imagine eating hamburgers for every meal. Hamburgers are delicious, but after a little while you'd get sick of them, plus you'd probably have way to much iron in your system from all the red meat.
Nutritionally, yes. They are very small, so as I mentioned, you will want to grow them out to their maximum size. They are high in calcium unlike most all other feeders, so do not need to be dusted with calcium powder. You will still need to dust other feeders with calcium and you will still need to use an appropriate amount of multi-vitamin powder as well (including on the phoenix worms).
You don't 'have' to gut load anything and I'm not totally convinced it does much good anyway, their little buggy stomachs are so small. I keep a colony of roaches and a colony of super worms and I just feed them good stuff all their lives so they are in general healthier to feed.