My spare "inventory of stuff"

I have no experience whatsoever with such a climate as I live in New England. However, from a structural standpoint, you might try to find a trustworthy contractor who could install three very large trees to balance the scale of the tall building with the ground plane. One tree should go in the space in photo #2 to the left of the deep end of the pool. The other two elsewhere in a triangular aspect. Perhaps one where the entry paving forms a corner in photo 3, and the third off to the opposite side of the pool. Whatever is in there now is just much to short. Make a serious investment in the proper giant trees for the conditions and the rest will fall into place. A lush ground cover all over would tie the place together. Whether it's soil improvement or just selecting something that is amenable to the climate, a uniform simple 'lawn' of low maintenance plants would make this peaceful. Visually, a waterfall would have to be enormous to look to scale here, and would have to go to the far end of the pool. Tricky to make that look cohesive. A water feature that creates sound near a sitting area is always welcome. A huge modern sculptural piece might be fun toward the left of the deep end of the pool. For style and realistic installation issues, you really need a designer, a plant expert, and a qualified contractor. You should stroll around town to find inspiration from you neighbors. Best wishes!

First, I wouldn’t do sod in this front yard. Too hard to maintain. I would put shrubs that match in color to your brick up high. Then on the slope low maintenance low profile junipers and moss holders for easy to care for greenery. I tried painting your bay window trim black but you can use your imagination. Paint all trim black. I put larger black modern exterior light fixtures for more light and interest. I added black pots with greenery to each side of front stoop. I would also like a pair of black slatted benches facing each other to flank entry doors. Couldn’t pull that off in this mock up. This will be showstopper home with not too much effort.

Beautiful entry. You really don't need anything in it other than a good no slip rug (and no stub/stumble edges). You could keep a small square or rectangle wipe-your-feet-rug and then in area between the cased openings consider adding an interesting round or oval or square one with your favorite colors (also non slip and with no stub/stumble edges). Prefer seeing the radiators. For decor, you don't "need" that shelving; it's higher than the wainscoting and both of them likely could be put to better use elsewhere. Were you using the shelving as a charging station or place to "drop" keys and sunglasses, etc.? because, if so, there is another option that might could work in your limited space -- perhaps a small narrow version of this on the wall. https://www.wayfair.com/Zipcode-Design%E2%84%A2--Jon-Floating-Desk-X115392267-L32-K~W004281156.html?refid=GX528945860062-W004281156_624721285&device=c&ptid=998723531694&network=g&targetid=pla-998723531694&channel=GooglePLA&ireid=130981889&fdid=1817&PiID%5B%5D=624721285&gclid=EAIaIQobChMIiarSip278gIVhrzICh1o1w3gEAkYASABEgJU8vD_BwE OR. You could block the view of the end of the radiator from inside the house by adding a pair of small narrow cabinets the same height and depth as the radiators on the indoor side of the entry -- a plant stand cabinet (permitting you to add a living plant or two to the entry) and with at least one drawer that could serve as a charging station (and more drawer or have shelves for baskets for collecting other pocket items). Any cabinet you like that meets your needs could serve the purpose, preferably one portable enough to easily move farther away from the radiator when it is in use: https://www.amazon.com/Cabinet-Bathroom-Multifunctional-Standing-EstaHome/dp/B087QK889H https://foter.com/plant-stand-with-drawer https://www.amazon.com/VIAGDO-Bathroom-Floor-Cabinet-Organizer/dp/B082HWNWV8/ref=pd_lpo_3?pd_rd_i=B082HWNWV8&psc=1 https://www.amazon.com/Stands-Multi-Layer-Drawers-Display-Minimalist/dp/B082H88BSC.