While I applaud the list, some of that you should not be hauling between the stars.
Water you should be able to secure on planet. If its a major action, you need to have your dropships set up somewhere near a source of water though this gets into having a water purification detail (as Cray says, Shore's In the Army Now). Food like wise can be requisitioned from the locals, which is historically what has happened until very recently IRL. I know it HAS happened recently in BT, b/c Ulric Kerensky oversaw part of that operation during the invasion (he also seized other supplies). Now unlike most historical examples, Kerensky at least paid for seizing materials, and you should too. Batteries . . . you can never have enough batteries. Just finding the right model to power your fricking ACOG is enough to give the supply sergeant headaches. If you knew how often troops used their own AA batteries from the mp3 players to get something working and when it was over took their batteries back.
Are you saying your men will not have anything to drink while on route to their destination? Even so I would at lest have enough water on board to last a few days on world till I can secure water sources. And what happens if I get forced off world before I can replenish my water supply's or prevents me from landing for a few days? Having three or four weeks of water would be quite useful.
One thing about food, a military ration's advantage does not really come out in our setting since the volume does not have an impact. Military Rations are compact, with a high volume of calories to mass. The flip side of that? Feeding constant military rations does not help your morale. Bringing in fresh food from the outside will be a morale boost for all your troops which must offset the security concerns. Dang, some of these discussions make me forget some of the simplification I worked before I started drastically increasing my unit size with armor crews and infantry (note to self, review mess section for mercs!).
Bringing enough "MREs" (or other such food types) for the force to last for some time, while in transit and on the ground is a very good idea, at lest until food sources can be secured on world, this particularly is useful if I'm a "hostile" group on the world (invader) as securing these sources may be difficult at times.
As far as medical supplies . . . again you can seize alcohol, some drugs, bandages and splints. Its when it comes to some of the more complicated items which are hard to get from local resources. IV Bags, stretchers, sterile needles and specialized drugs are going to be harder to find . . .
And while it may make folks cringe . . . seizing a hospital during an invasion's advance would not be a bad thing strategically. Sure your MASH/CASH does some very good things for you, but a purpose built facility would increase your survivability for casualties, as well as response time of resources. Which might mean you want a MedEvac VTOL per company?
I do not think it's a good idea to skimp on these items, it may be a good idea to use the world your going to to provide replacement stocks, but if your the hostile party I would make sure that I have the basic requirements down.
If I'm reliant solely on raiding these sources for my forces medical care, it says to my opposing forces that I am not fully supplied and gives me a weak point if they see it in time to exploit it.
Now "acquiring" a purpose built hospital can be useful, but I would not want to rely on it as the linchpin of my on world medical forces.
Though it all depends on what I'm going going to be doing on world. If I'm garrisoning, then I would need to bring less equipment as much of what I may need can be found one world and systems in place to easily allow my forces to acquire what they need.
If I'm invading then I'm going to want to bring as much supplies as I can get a way with, as I'm on a potentially hostile world and replacement items may be difficult to acquire in adequate amounts.
Their is how ever little need for the unit to bring six months worth for many of these items, a month should do well enough for most needs, until on world sources arrive.