Awesome to see some traditional art! Quite an ambitious project you have going! :D Something I would consider is having some of the leaves and foliage in the background "go behind" the silhouettes, that way you'll push those areas back in space, and the lion and figure will come forward a little bit more, helping with the sense of depth. If you think of the areas of foliage abstractly as large shapes, they are all sort of "dodging" the silhouettes of the lion and the human, making the image feel flatter. It does give a kind of more graphical flat look, which isn't bad in and of itself, but I don't think that's what you're going for, when looking at the overall approach.
My mind goes directly to the absolute daddy of academic art, Bouguereau, especially in the way you've handled the background. Something that I think you should consider is the visual hierarchy of the piece. Take a step back and ask yourself the question what you see FIRST when you look at your painting. Are your eyes drawn to the lions face first, or the figures face, or the hands, or the trees in the background? etc. Personally my eyes are instantly drawn towards the foliage, because of clearly drawn everything has been, the dark spaces between each individual leaf and just the overall contrast. I don't feel like that's the intention of the piece. To me it's clearly a portrait of a human and a lion, and not a painting about some leaves in the background. So I would absolutely look at how Bouguereau handled foliage and background elements. Don't be afraid of loosing some of that contrast you have going on and make it a bit more subtle.
If this is done in oils, let those areas dry completely and afterwards I would start to scumble in some new leaves that will break up these dark areas around each leaf. Dilute the paints with a medium being like 50/50 oils/solvent, it depends on what kind of medium you've used elsewhere. If you've used a very oily medium before don't go in with a thinner medium on top. It can cause problems down the line. Good thing about oils and letting it dry completely is that if you're not a fan of the way it looks, the new leaves, you can simply wipe it off and go again. By going in and introducing the new leaves thinly allows you also to just try something out without huge consequences. If you like the way it's going, then you can start to introduce more opaque paint into those wet areas and painting wet in wet in oils, that's where so much of the yummy magic happens. This is how I approach oil painting at least, everyone will find their way but yeah. You know what I mean haha :P
Pay attention to how loosely Bouguereau handles foliage. I'm not saying I would go as soft (maybe I would haha, i absolutely love the Bougs) but I think something in-between your high contrast and his low contrast will be a huge improvement. For me personally it also comes down to the question of "will the viewer understand what this is?" and perhaps I don't HAVE to spill everything out so clearly.
