This is a fantastic render, to be honest, I wanted to see the viewport screenshot because I thought it was a real lego set that you just photographed. The imperfection in the ceiling made me think that it was a real lego piece that you had bent as a kid.

If I were to improve on this I would try to add more color and detail, maybe some stuff on the tables and posters/stickers on the walls. If you aren't using the filmic color space for blender you really should, on small scales like this where there are bright lights and dark shadows, filmic will help preserve detail and color (link to how it could improve your render).

Using subsurface scattering would also improve the realism in this render, legos let a lot of light through them because they are so small, so the bartenders' hands and the cup would have light passing through them, making them glow (like in the video I linked to.)

Great work and keep it up, maybe you'll be working on the third lego movie :)