Propagation: Do I have a problem?, 1 by amfm

amfm wrote:
This is a flower mix of Zinnia elegans 'envy', Verbena bonariensis, and Salvia farinacea 'Victoria Blue'. I started the seed inside on April 3. Each of these seems to germinate at different times and I don't know enough to tell the seedlings apart. Some of these germinated within days, some took a couple of weeks. I noticed this week that some of the leaves on the seedlings that germinated quickly are shriveling up and the seedling is dying. I didn't think the seedlings that germinated later were big enough to transplant to the garden yet. Was I wrong? I can take more pictures if needed.

also, as for not knowing the difference in seedlings, do they usually look the same? I have some bee balm and sunflower seedlings that look pretty much identical.