I am not sure you still need an answer to this (sorry, I only saw this now). In case you do:
Grocery deliveries - generally yes, you need to be there. If you have something sent via Amazon Prime, they will typically hold it for you and send you a text saying they received a package for you. When you get back to the room, you can ask Room Service to bring the box to you. But that is for non-perishable / non-refrigerated items. For perishable items, my experience is that you need to get them to meet you in the lobby. I was once able to get Garden Grocer to deliver to Portofino Bay, but that was during the height of the pandemic. I am not sure they would do it now. Depending on who you get for the airport transfer, many companies offer a free grocery stop. Why not ask them to stop at the Publix on 9030 Universal Blvd, Orlando FL 32819? You can even pre-order the groceries for curbside pickup so that it will be a very short detour. I set this up with Ace Luxury Transportation, but I think many other companies offer a free 30 minute grocery stop.
Milk - I do believe they have this at the convenience/gift store near the lobby, but the selection is extremely limited. Obviously one solution is to have groceries delivered. Another solution (if you plan ahead) is to order Shelf-Stable Milk from Amazon. These do not require refrigeration, so it can be shipped as a normal Amazon Prime package and they can deliver it to your room. If you have never tried Shelf-Stable Milk, it tastes almost exactly like refrigerated milk. The primary difference is that Shelf-Stable Milk is heated at a higher temperature during the pasteurization process and then sealed to keep it fresh for up to 6 months. Once opened, it acts exactly like the typical refrigerated milk. There are many different brands of Shelf Stable Milk - Natrel, Parmalat, Horizon Organic and Organic Valley, to name a few. I think Walmart and Target also sell this milk, if you want to avoid Amazon.
USB Ports - While I counted 10 available plugs in the room, and 4 available plugs in the bathroom, I did not see any USB plugs. I would bring chargers with a USB port.
Pool towels - I think someone already answered this, but to also confirm, yes, they have these and I have never seen them run out. There are also typically 6 lifeguards on duty at any one time at the Beach Pool - I think this matters if you have kids and want to rest a bit.
How to charge things to your room at the Parks or Citywalk - In my experience, they will always ask for your room key so they can scan it. I never bring my credit card with me while I am on property. I just have them charge everything to the room by scanning my room key. I also always have them deliver all my purchases to the room - it always shows up the next day, usually by mid-afternoon. The charging priviledges work at all 3 parks and at Citywalk. On one trip, my kids went nuts at the Diagon Alley stores and we went over the daily charging limit that the hotel applies during check-in. It was very easy to get it bumped up - the store clerk called the Portofino front desk for me and it took less than a minute for them to look up my account and then increase the daily limit.
Some other commentary:
Where and how to do room requests - I have had luck emailing portofinocustomerservice@loewshotels.com and I ask for a room in the West Wing. For me, I want to be near the water taxi due to mobility issues, so I ask for the West Wing and ground floor. I also ask for the room to be defeathered. I am not entirely sure what that means, but it seems to make the room just a little cleaner. In my last trip, I was able to get a room that was 50 steps to the water taxi - this was for a Bay View room. But it is possible to get a room in the West Wing if you reserved a Garden View, it just won't have a sliding door opening to the piazza (near the water taxi).
Alarm clocks - unlike Disney, the hotel rooms do have alarm clocks. Although it is much more fun to set the wake-up calls to Spiderman or one of the other characters.
Musica della Notte - just ask at check-in what the schedule is. Or email portofinocustomerservice@loewshotels.com if you want to know ahead of your trip. More informally, the singers tend to come out around 7pm (sometimes it is a little later at 7:30pm). But this is outside of the Harbor Nights festivities.
Trattoria del Porto - this is hit or miss for me, but one night we had a fun experience. It was a Saturday and they brought in a magician that day. We managed to go when there was a lull in crowds and we were one of two families with kids - and the other one had toddlers. The magician setup in the table next to us and spent the next 15 to 20 minutes doing magic tricks for my fascinated son, who was 11 at the time and thoroughly impressed at having a private magic show. While it is hard to know what acts they will bring in, if you happen to be there on a weekend, you might want to stop and ask. They may have a fun performer planned.
Suite questions - I recommend emailing portofinocustomerservice@loewshotels.com and asking to forward your request to the Rooms Controller. Explain what you want and they can recommend the best suite configuration for you. This is because different areas of the resort have different room configurations, so if you want the West Wing near the water taxis and Beach Pool, then they will have different options than say the East Wing, which has the Villa Pool. Suites also get booked quickly, so they can help you think through different options based on availability. The Rooms Controller can also tell you whether or not it will have a balcony (or patio).
