Houzz is the new way to design your home.
Look at the sofa with legs on the wood floor. Also idea of a square coffee table
Sideboard is antique, set against modern sofas (to floor on rug)
You could always have a footstool idea instead of a coffee table so that you could put your feet up too
I like the idea also of two individual chairs instead of the second sofa - then you can put a little table in between.
Here is another look...
Look at the little table - glass in corner - really nice
This actually looks really like your house. With this formation, you could actually create a lot of seating area and the different colors create interest.
This is what it would look like if you didnt keep the rug
Matching lamps that are unique looks good
Nice mirror over mantlepiece
The two footstools are quite a cool idea and I like the glass coffee table.
That is an example of a sofa table - it is a narrow table behind the sofa.
Kinda like this but I dont like the dining set
I guess you need to decide on what the function of the sun room will be - but with kids down the road, you will want an area to eat every day meals as a family.
This is nice for sun room but I really think you may need a dining area in addition to your formal that you are planning. Also that art studio would be a great kids play room down the road too.
Simple and elegant dining
This is what it would look like with dining in sun room
It could be a whole other seating area
You could just have a couch in foreground and all facing towards TV on end wall