Absolutely you can mix traditional windows with contemporary window treatments, although I don't think plantations are considered contemporary by any means. Ordinarily sash windows can have shutters installed over them, however I can see your sill is very narrow given your bottom pane sits forward of the frame. I can see privacy is no issue, in fact you have a great view and half height windows allow light in and keep peepers out, so I suggest plantation shutters fitted to your French doors, to allow tilt and directional light and a roman blind as the folds of fabric mimic the frames themselves to your corner arrangement. If they are too fussy for you a standard holland blind, however be creative, you can have a bonded holland which allows for a fabric front bonded to a block out backing, you can ask for a roman fold on the bottom making them look like a roman when rolled almost all up, and dress the window a little better, but Hollands can roll up into the frame and allow for maximum window when wanted.

Search modern country on Pintrest and Houzz. I was looking yesterday at lovely houses. I stumbled on them as I didnt think modern country would be my thing.

you need to confirm all the dimensions as there's some discrepancies in the sizes shown in your plan but my suggestions include losing the linen cupboard in favour of a bigger bathroom with space for full size bath, shower, vanity and toilet with linen storage in the vanity under the handbasin and toiletries in wide wall cabinets over the sink and toilet...there's a sliding glass door off the kitchen to an enlarged deck and a galley kitchen with old laundry becoming a combination laundry and pantry with wide counter for under bench washer and blind corner pantry and space for the fridge and removing only portion of the wall allows for an opening between kitchen and living with space leftover for stove, counter, drawers and wall cabinets and more counter with double sink, DW and drawers on the other side

Keep the meals as is. As this is the west side of home. Because your lounge is a thoroughfare, and you said in another post you are installing a wall. Then maybe keep as is. Ideally the lounge should have a big window, since it is on the north side. But if you have no where else for artwork, and you are overlooking a fence, keep as is.