Hi I been meaning to add an aura type of effect to objects but the ways, I've tried were not satisfactory. I tried the compositor adding blur nodes but didn't look right. I also have thought of maybe using layer weights and then used fresnel to make it look like the edges are glowing. Then after watching Coco for like the bazillionth time, the scene where Miguel sees his dead family I liked the way they had a light that surrounds each one individually.
Create a Glow Layer
You separate your render into two, the normal render and a glow render, both layers with a transparent background, in the glow layer set all the objects to have the same material (use an emission shader with the color of the glow you want):
Then, you can use this Node Setup in the Compositor:
You have to take into account that, in this example, the lighting is lame, that's why the effect doesn't look realistic, but using the same lighting that your scene will give you great results