Right now we can dynamically change color and some other material parameters of objects in our developer viewer: here is an example.
1: added default material
2: clicked "do not batch" in our tab in object options, exported to .json and opened in dev viewer
3: selected my cube and pressed tab "materials"
And now the color can be changed dynamically :)
Note: it works only with non-node material (we call it stack material)
Size, location, rotation etc. can be changed by using NLA script
Hope it'll help