You need to draw the overhead dimensions out on graph paper to get an accurate idea of the space and what to do with it. Also draw the adjacent spaces out so that their relationship to the area can be seen. If this area was a porch, I would be concerned that it lacked the proper foundations and insulation to be an interior room, so you need to investigate that, as well as the roof joining to the main structure. Those are problem areas that give rise to structural damage that you may not see until you begin a project.

you really have NO walls to decorate except where your plant is. there must be somewhere else for it to go with better lighting. once its moved add a large mirror like the one CITYFRAMES posted. I feel a mirror will help with the lighting and help the space feel bigger it will be hard to find something that narrow to fit on the wall by the front door. you could look for a small storage ottoman for shoes and a place to put them on and add a floating shelf above for a place to set things. and then look for some art to place above it. I did find this though

Here's what I would do. Clear everything off the walls and remove the table & lamp that are by the entry and front window. Place the sofa like it is in your first two pictures. Empty the tall black bookcase, take it to the opposite wall and lay it on its side. Use it to put the TV on and decorate the open shelves with large decor items. If you feel it is too short, add some feet to it. Leave your current TV stand where it is in the foyer. Put the lamp on it and lay out your pictures on the carpet to see if any of them need to go above it. Here is a before and after of a redesign I did changing the usage of a black bookshelf. Sorry the lighting is not good, but she turned the shelf on its side and gave it a new look and purpose. You can do the same here. Before After

la_la Girl has a good idea. You could order a custom shelf from Etsy. Just put "cubby storage bench" in the search box on the Etsy site. Also "coat rack shelf" When I put those search terms into the Wayfair search box, these came up. You could order two side by side for everyone's shoes, adult shoes included! Get two hanging shelves. Hang one low for kids' stuff and one higher for adults' bag. Put clock and mirror above them and some family photos for a friendly entryway. Here's an Etsy link to a page with a ton of customizable coat rack/shelf combos. Get a good sized bench and rack since you have the room. https://www.etsy.com/search?q=hallway%20coat%20rack%20with%20shelf Etsy link for "storage bench cubbies" https://www.etsy.com/search?q=storage+bench+cubbies If kids are little, open storage is probably best for now. A beautiful clock above, a nice, mirror, family photos, and a great rug that goes with the rest of you house can make your entryway practical and attractive. Here's a tip: make a game out of training the kids to put their shoes in the cubbies or baskets. Stop them right at the door. First one to get shoes in the right place, coat & backpack hung up, gets a treat or a star. Teachers train kids to do this all the time at school.