personally I like beadboard with clearseal. light and shows the beauty of the wood. also light wood opens up the space. you could stain it to whatever color you'd like. but... before you install your beadboad put an air barrier on the joists/rafters. I find that wood ceilings leak a lot, when I blower door test the house. this entry for hot/cold air to enter has a big effect on the comfort/efficiency of the house. we use tyvek material attached to undersides of joists/rafters, draped down on walls for sheetrock to be installed over it. then attach the wood to the tyvek covered area. (ceiling joist or roof rafters depending on type of ceiling you have) also putting the beadboard on a diagional is a look I really like. (but that's just me) best of luck.

As floorguy has mentioned the sky is the limit. Personally I like a log cabin type border design in the corners rather than the mitered one shown in the picture. Nifty designs in the center? Sure, I've even found some custom stuff can be manufacured for a reasonable price. Here is a link that might be useful: hardwood design ideas

You've already had good advice -- and the Sarah Richardson paragraph is great. I thought I'd give you our experiences with painted floors and pine, since we also have Beagles. First, the pine. I agree. Don't use it; use a hardwood instead. When we bought our house, most of the floors were southern yellow pine. We had them refinished. It didn't take long before there were deep scratches, especially near the exterior doors. Picture three Beagles dashing to the door whenever someone comes in or out. Also picture mad chases around the house on days of pouring rain or deep snow! I would NOT use pine. Painted floors. To save money after tearing out horrid carpet upstairs, we temporarily (for about 8 years!) installed oak faced plywood in a couple of rooms and painted them with floor/porch paint. One room got daily use as we walked through it to get to our bedroom. Because of its location, it was part of the long "raceway" between the two end bedrooms upstairs. Again, lots of fast and furious Beagle traffic. The floors survived much, much better than the pine floors. They were painted a deep blue, so had they scratched like the pine downstairs did, we'd have seen it. Of course, we're in New England and don't have Florida humidity.

haus, I will give you a few of my experiences as a consumer who built a deck and screened in porch area for our home. 1. not sure how well the skylight will work, however we had the same concern and we ended up building our screened in area away from the house for the very same concern you stated. We did not want to lose any natural light in one of our rear rooms. i do know someone that did a full roof out of plexi glass for the light reason. it works well, but keeping it clean is a pain. 2. agree, minimum roof height should be 8ft. I did a 9' ceiling that is valuted up to 12' 3. screens. all kinds of options here. I ended up ordering aluminum screens made up to fit the openings I framed out. they are aluminum frames with "super screen" material. I ordered them on line from a vendor out in colorado. it worked pretty well, and they were about 35% less than anything i could find locally. they are screwed in with screws that have been color matched to the frames and they have held up well in some very strong storms thus far. if one gets damaged, i figured i can take out that individual screen and have it repaired locally. 4. no help on a floor that you can paint. i used IPE tg floor in the screened in area. 5. wide open here, you can buy one or make one out of the same materials used on the project. i ended up putting in a sliding door, but mine is not an opening to the home. 6. not sure... built it myself. Not sure if that helps, but we walked through a lot of the decisions that you are considering. Take your time and get what you want. I posted a picture for a visual.