I think the roof might be a bit too dark for the brick colour. The bricks and the window joinery will blend in fine. What did you decide to do?

There is nothing worse than ceiling-mounted lights--harsh shadows, flat lighting. They are strictly for utility. I would put a large-ish, shallow cylindrical shade on them and put nothing more than a 15-watt bulb in them. Use them strictly for lighting your way as you walk through the room. I agree with Vincent; the chair in the corner doesn't fit at all, nor does the one under the A/C unit (put that one with its mate behind the love seat). And the curtains look smooshed. I think the problem with the bookcases is that they are uninteresting. Did you buy books-by-the-yard? What are all those identical books? They are visually uninteresting. I'd get rid of some of them and get some colorful ceramics/glass/photos. The room is absolutely overwhelmed with furniture. It needs one less love seat. Do you really need all of them? Pushing them against the walls/curtains so tightly just visually emphasizes the fact that there is too much furniture. I don't think a mirror above the fireplace will work. When people are sitting down (which is most of the time), all they will see is a reflection of the ceiling--the plain, white ceiling. Get some real art in there with some color.

You say the kids come in the small door and then bring their stuff to the large door to drop it? I think the "mudroom" needs to be at the small door. Anyone who brings their stuff out of that area has to clean the glass doors next time they need it. As for the guest entry, you need to get something bigger than that desk, and your picture needs to be lowered so the center point of it is 5' above the floor (you'll have to calculate the centimeters.) Consider making the investment to reverse the swing of the door so you can make the best of the larger wall to greet your guests with a console or credenza and some decor.

We have a 900x900 shower and it's plenty big enough. Neither of your proposed layouts looks that great, to be perfectly honest, sorry! In the first layout, you could improve it quite a lot by swapping the toilet and vanity (centre the toilet under the window on the bottom right of the picture if possible), and having the shower door on the other wall (beside the door). Then, you could have a towel rail on the wall beside the door (i.e. behind the door when it's open), which would be accessible from the shower but hidden when the door was open. An 800x1200 shower might be a good size for your space. You'd have to choose a toilet that doesn't protrude too far, plus a narrow vanity. With that layout, you could have a long but narrow wall-hung vanity, with a big mirror covering the wall between the windows, which would make the room feel bigger and would give a good amount of storage. Also, you may find this helpful: http://www.houseplanshelper.com/small-bathroom-floor-plans.html?utm_content=buffer4aa20&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer