"Lucy" is particularly sweet.
Can't tell you about the lighting, as I don't have indoor trees, but I will tell you that your appreciation of bonsai will grow and change as you read and learn. We all start with younger trees, and as we learn to keep them healthy and prune and trim, we also learn about how to choose more advanced stock. Your passion for learning will determine to a great extent how quickly you move ahead. And it looks like you have the bug.
Learn for now how to keep your trees happy, and do lots of reading.... your juniper is nice, your ficus are going to be a lot of fun, but Lucy has potential. The trunk being larger gives her an advantage. The thing is, you want to give the illusion of an old tree, which is more convincing when you have a larger trunk diameter in relationship to the height. The juniper may eventually get a bigger trunk but it will take a long time in the little pot.... like fish, bonsai grow bigger when they have more room. The ficus look very immature now, and the forest was a good choice, it will give you an enjoyable image while they grow out. Ficus grow fast in the right conditions and you'll have good chances to pinch and prune.
The little rocks on the juniper, if they are glued on, will need to come off. Rocks are put on the surface and glued to keep the soil in place, but when you water over them they may inhibit the water and the oxygen from penetrating the root ball. Looks like you are using rocks also on the ficus, to mulch or keep the soil in place. Make sure the rock isn't too thick and that the water penetrates quickly. It's better not to have them at all, especially since you need to be able to tell when the soil is dry. Don't keep your trees too wet, make sure to let the soil dry slightly first. When the top is dry but the lower level is just damp, then you water. Especially with the juniper, they die easily of root rot.
If the windows are very cold it could be harmful to the ficus'. Keep them away from heat sources as well. It looks like the heater vent is under the window sill. If the heater comes on, it will dry them out quickly and they will be crispy critters. Think of Goldilocks... not too hot, not too cold, not too wet, not too dry.
Well, that's a little info anyway.
Good luck and welcome
Joanie