Convert json files to geojson EPSG 4326

I have these json files but I need them to be converted to geojson files. I have tried converting them before but it did not work and I am looking for someone with a better skillset in it to help me do it. I know this actually pretty easy but with time constraints, I am looking for some help. The json files are below. I am trying to use these to create custom maps in Mapbox Studio. Also attached is the warning message I get from Mapbox when I try uploading these json files. I will look like to test it in Mapbox to make sure it works as well!