I hope pedestal sinks aren't out of style. I just ordered one from Toto for my master bath renovation! You shouldn't have any difficulty finding a stylish sink in a pedestal or wall mount style. I suspect you may be far more limited by what I think is the very small size of the sink that will fit. You may need to just start googling. But yes, I think you can put in a pedestal or wall mount and look up to date. Sorry I can't be more help with specifics. I keep reading that larger tiles make a room look bigger, so I would put in the largest floor tile you can find that you like and doesn't look ridiculous, laid on the diagonal if you want it to look even bigger. But I would definitely do tile of some kind, not vinyl again, unless you're going for a very specific sort of retro look. Definitely a round, not elongated, toilet, no matter what the salespeople tell you about how much more comfortable the elongated is. And, depending on the exact configuration of the sink, I'd be careful about the height of the toilet. Some of them now come higher, sometimes called right height, I think. It's supposed to be easier on aging knees, etc, but if there's an issue with tall people needing to tuck their knees under the sink, you don't them to be sitting up too high to do that.

Do you have a separate Dining Room (this is where it would help if we saw the layout of the entire floor - both here and on Kitchens - not just the addition, the entire floor). I'm asking b/c if you do, you might consider making the table space a banquette and taking more space for the Powder Room. (Bench along the Powder Room and, possibly, "top" walls) Regarding the laundry - I'll be honest, I would not want my laundry anywhere where guests could see it - and putting it in the Powder Room means guests will definitely see it! It might help to build an enclosure around it - it would at least hide the washer & dryer, but it wouldn't help with any laundry sitting in the room - clean or dirty. Note that expanding the Powder Room may mean going with the narrower window (8'+ vs 10').

can you put a wall mounted toilet in that room. It would mean more money and the tank is mounted within the wall. I am not sure how the floor waste drain would be reconfigured. Depending on how waste drain is managed, it could mean that you could mount the toilet on the other wall. But I don't know.

Yes, toilet and sink can remain where they are. I would have one hanging hand towel space near the sink - disposable towels are great if you have a large number of people over at once, but for one or two at a time, it's not so luxurious, and rather wasteful if you are dashing in there yourself when home alone. Under the overhang... a cabinet to store supplies, including extra TP. Find an attractive knick knack for atop. Either art or wallpaper on the wall behind the toilet- or perhaps through the entire room (edit, wallpaper that is...) Paint or paper the slope the same as the wall it is on. If you are apt to have guests who are older, or may have physical limitations, consider a comfort height toilet. It would probably be worth changing out the tile, but you can always use the right rug for now.