Unless I have bad eyesight, these plants look fine.

The yellow spots are early Downy Mildew. The white you say was likely Powdery Mildew. Both are fungus problems.

Begin regular fungicide applications and remove affected leaves. Increase sun exposure to the max possible and avoid over-watering until the soil dries out quite a bit. Wet soil encourages both..

You don't indicate your location or zone but in most of the country it is too early for the plants to be mulched like that. So unless you are in the deep south or So CA it keeps the spring soil and surrounding area too cool and wet. I'd suggest pulling it back from the plants so the area can dry out some. The replace it once the soil temps reach summer levels.

Dave

Thanks for responding! I went ahead and removed the affected leaves and applied fungicide. I also moved the mulch out of the way. Today I noticed the cotyledons are nearly all yellow- this is normal, right? I keep reading that they eventually wither and fall away, but should they yellow? Thanks again.