Magnificent!! Looks like a beautiful park.
Some suggestions to compare to your plants:
Sulphur Cosmos (Cosmos sulphureus)
Cosmos (Cosmos bipinnatus)
Threadleaf Coreopsis (Coreopsis verticillata)
Sweet Alyssum (Lobularia maritima)
Evening Campion (Silene latifolia) (or maybe a different Silene)
The mix should have a list. If you still have that, or can find it from vendor, that would make it easier - match bloom to name. There will be other things coming up that are not from the seed mix. To stay on top of things and hopefully notice any unwanted plants in time to pull them before they drop more seeds, you can ask about each mystery plant in Plant ID forum.
https://garden.org/forums/view...
It's less confusing when there is 1 plant per discussion.
I see some of these confounded things in your pics:
Tropical Mexican Clover (Richardia brasiliensis)
I think they would probably get along OK with the taller flowers you have, and bees/butterflies probably like the little blooms, tough enough to take moderate foot traffic, and will help shade the ground so it doesn't bake dry so quickly, if that's an issue where you are. I don't have space to share with that. If you decide to evict, they make a little tuber, so if you don't want to pull the same plant over & over, pry that tuber loose before you pull and pull the whole thing the first time.
Others that grow so easily from seeds:
Zinnia (Zinnia elegans)
Marigold (Tagetes)
Larkspur (Consolida ajacis)
I think I saw some of these in your garden already:
Sunflowers (Helianthus annuus)
Any of the milkweeds, so beloved by bees, hummingbirds, butterflies:
https://garden.org/plants/sear...