So for context my input comes from working with hospital security for a major hospital chain environment. Some hospitals may have different policies, but from what I've observed most of what policies and procedures I have observed is Industry wide.

Majority of the products you've identified are fine except for; any consumable food or water products, hygiene use products, and in depending on your outlook; medication.

The reason I say this is because if you're going to the ER it's likely that your going and possibly becoming an inpatient; i.e you move from ER Triage into care center (surgery, ICU etc.) and become patient for at least 1 overnight stay.

When this occurs, from a policy and security standpoint you are essentially stripped of belongings. So if you're in ER, you're triaged to need to go to more deliberate care and treatment, security will go and take your belongings, inventory it down to the last cent and pen, and store it usually in a bin that is ziplocked then stored with security. When your getting discharged security will take said bin, and return your materials with a meticulous list of all the things inventoried in which should match since it was sealed. You normally won't be able to hand bring your belongings, even when you're in a step-down or care unit, you have to work with the RN or MD to get your stuff back from security, unsealed, get what you want (if it's approved) and then revealed.

Problem is; there is some materials that can't be sealed. This is due to health and safety hazards, to include: food and water (perishable), non perscription/illegal drugs (disposed of due to liability, and illegal in conjunction with law enforcement) hygiene products (poses a cleanliness and storage issue, especially if products break in storage, or cause scent concerns, overall most hospitals dispose of it after a set period usually 1-3 days, exception to paper based products like bandaids or tampons) and even prescription medication (what happens is security takes it and gives it to pharmacy to input into your file and return upon discharge). There are other items too (lighter, cigarettes, vapes, weapons, soiled clothing etc.) that are not sealed in the property bin but taken, sub inventoried, and stored separately in other designated areas or disposed of.

Additionally; I will say that the more stuff you have, the larger the risk and the time to both enter and discharge increases. Risk because security is human and some officers are lazy/lack attention to detail so fail to record everything, possible 2+ bins for storage that get separated, and etc. But also time because the more shit you have the more stuff that needs to be inventoried both upon entry and as they return it to you!

So overall, as with most things; more is less. Most hospitals have vending machines, or even offer water or snacks if you ask. Hospitals have all the supplies you need, even if you were bleeding in the ER talk to the receptionist or security staff and they can usually give a bandage, especially masks. Additionally once your a patient you're provided everything from clothing to hygiene products to food. Personally the only things I would ever bring having known the backend of it is my phone electronics and charger, maybe a book or two, my clothes on my back and maybe a set of clothing, and car keys/wallet (no cash).

Just perspectives from someone who worked ER security and had to do this type of work for all ER intakes.