I’ve found time to have done it. It was less complicated than I thought. 
It ends up being a combination of 3 emitters.
1 for the main texture that dissolves, 1 to spawn particles on the edge of the dissolve, and 1 to spawn particles from those particles because in order to dissolve the the first two at the same rate, they need to have the same loop duration or all the particles dies at the end of the loop.
So I did end up having to sample a mesh to use it as a spawn location, and then I just use a custom scratch module that is essentially the combination of kill particles and sample texture (use UV of mesh to do so) with the dissolve effect I wanted.
Please lmk if there’s anything I should do to improve/optimize this!