Shutters sound like they would be a great addition to your new almost at the beach house. Is it an open concept? If so while you can change things up a bit you'll want to repeat some element and ensure that everything looks great together. Even the rooms you're thinking of putting drapes in might benefit from shutters or wood blinds for both looks and light/privacy control. Also be aware of how these windows will look from the outside. When choosing fabrics look at your existing furniture for inspiration or a piece of existing art or if buying new furniture think about the windows as you do. Everything in the room ties into each other. Ideally you would have swatches and samples of every finish in the room from flooring to window coverings and everything in between including wall colour, area rugs, bedding ect to help make your final decisions easier.

Nothing will affect the feel of your house as much as the quality of the light. If you can at all swing it, keep your divided lights. Looking at your photo, those windows are gorgeous. Can you place glass on the exterior? I have some lead light windows in 2 locations. I made new frames with the leaded old glass on the inside and plain glass on the outside. While not as weather-tight, it's much better than single glass. While not as neat as your present windows, the new windows that have the interior and exterior lights with the spacers between the glass also look great and are at the present standards for energy efficient. We live in the PNW and used Milgard; less expensive than Anderson and Marvin, but so far I'm very happy with them.

Top down bottom up blinds? They come with an aluminum coating too (to block sunlight and thus heat). In our bedroom we installed 2 roller blinds on top of eachother. Both white. One translucent for privacy and one to darken the room. It was cheaper that the dual layered (cellular) blinds and I did not want foil. Not sure if you'd have the space for that (we insulated the walls from the inside, so our window frames are quite deep).

These houses were designed to look good from the street, regardless of what the orientation was for the Sun. Everything depends on your budget and how far your prepared to go. A friend's house in Queenstown faced the street, the toilet and bathroom had the best view of the lake and the Sun. They got a house removal Coy in, jacked it up put it on the truck drove out and turned it around and reconnected all the services. It then faced the North and West great views and warmth, doubled its value in 3 days!. I replaced my storage water cylinder with a outside gas one, picked up enormous space in our laundry. Another tip is to draw up your "dream" plan, then overlay it over the existing and see what you can really do, your then not influenced by what is already there, and often get a much better insight and removed from the existing. Good luck, its very rewarding and make it fun!