I’m afraid I’m not going to be too much help— I don’t know why these “kits” sell you this idea that you should be able to grow these trees from seeds. Truth — I would not have confidence in myself to succeed. So my first instinct is to reassure you it won’t be on you if these babies fail to grow. I know — not very reassuring.
That said, it’s critical to research as much as you can about the kind of care each of these need. Do they need same kind of light, growing media (they would need bonsai specific tree in container growing media as they grow out of seedling stage), temperature, soil moisture, humidity. Does any if these need winter rest period. etc.
Ultimately, trees tend to be slow growing and you need a lot of patience to nurture them from seedlings into actual bonsai. It’s much better to take shrub-like or vine-like older specimen that are growing in the ground or in nursery pots, and slowly trim and prune and train them into the shallow-root mass and desired shape expected of bonsai.
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