Marvelous is definitely becoming more popular throughout studios, and is becoming more of a go to solution for cloth simulation. If you are a character artist, it would be silly to not at least look into it and give it a go. I personally love the software and have found it immensely helpful in dealing with any type of…
that's a list of numbers - humans can't do anything with it someone will have written an importer for blender/max/whatever - find that and use it . the RDR/GTA modding community is fairly mature afaik so its unlikely there aren't tools and tutorials