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This article covers the most common problems with peas: https://www.gardeningknowhow.com/edible/vegetables/peas/pea-plant-diseases-and-pests.htm

Since it's been a year, I would not worry too much about having any residue leach into the soil at this point. The peas and other vegetables should be fine. To err on the side of caution, however, just make sure that you wash them off thoroughly prior to eating.

Purple peas are a member of the group commonly known as southern peas. There are altogether maybe a dozen or two different varieties and cultivars, and they come in a number of different color variations. There are no diseases that I can find that cause pea pods to turn yellow, yet don't affect the leaves. I think that, despite the label, your peas are not "purpling," and you're missing the harvest, so that the yellow is the color they turn as they start to dry. Go ahead and try some when they're nice and green and fat, and see how they taste.

Yes, it is possible that something has eaten your early planted peas. Birds and/or mice are commonly the culprits. My best guess for the "whitish somethings" in your soil is that they were part of the pea seed coating that was shed as the seeds were undergoing germination.

Since these are nitrogen-fixing plants and if they are healthy with exception to not blooming, they likely do have too much nitrogen. Give them some phosphorus to balance them back out. Bone meal is a good source of phosphorus and will help encourage flowering. Here is more information: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm