In Geometry mode the shapes (built-in or custom) bring their own UVW coordinates, so texturing is trivial. When doing any kind of metaballs, the UV coordinates are transferred from the particles to the mesh via the field data, so things can get messier.
The Magma approach lets you assign any data to any TextureCoords channel (from 1 to 99), plus Color, so it is rather powerful. But you can assign UVs to Particle Flow particles too, and that data would make it over.
So the first question is - where does the data come from? Do you mesh a particle source directly, or do you first bake to PRT (or something else), and then load via Krakatoa PRT Loader, or via the Particle Files options of Frost itself?
For example, this video shows a Particle Flow acquiring UVs from a mesh object at birth time: https://youtu.be/GyWRy1m-6eI
The UVs then persist over time, so as the particles move, their UVs propagate to the Frost mesh.
If you use mesh vertices as the source of the Frost particle cloud, the UVs of that mesh would propagate to the Frost mesh, so the resulting Metaballs, Zhu/Bridson etc. isosurfaces would look very similar to the original object if the same textured material is assigned to both.