As already stated several times: If you know what you need to do on a glacier, you know what material to take. The other way round does not work: Just having the necessary gear will not insure proper crevasse rescue. So your first step is to take a course or find someone experienced to show you. This is the only recommended way to do it, but that is of course meager for Q&A, so I will try to give some information, but they should only be supplemental.
The questions How to walk as a roped party on a glacier? and How do I rescue someone out of a crevasse? have already much information in them.
E.g. rope length is explained in the first question. For three persons it is 12m in between, excess ropes equally distributed to the two persons at the ends. Now how much rope you need is determined by your worst case scenario. If you just want to hold a fall, build an anchor and rely on the fallen member to self rescue (which is always the fastest and easiest way if this member is not injured) 24m of rope is just fine. If you need to pull the fallen member out, it gets much more complicated and there are several systems with their benefits and drawbacks. The maximum rope required in all the pulley systems known to me (for crevasse rescue) is three times the distance between the final anchor and the member in the crevasse: One third the initial rope to the fallen member (obviously), two thirds for the pulley (as the first section will have cut deeply into the snow). So assuming you can build the anchor at the position of the member in the middle, you would need an extra 12m, so realistically 40m (36m rounded up). What kind of rope is really not important for glaciers, as there is no rock and thus sharp edges. A very good and tested but somewhat advanced option is using aramid/dyneema ropes. These are suited for glaciers, light and do not take up much water. But you need to know how to handle them, some knots do not work the same as with traditional ropes.
In your list there is nothing about materials to self rescue and/or build a pulley. For self rescue one safety biner and two slings are the minimum required. For a pulley it again depends on the system, but one progress capture/one way blocking device (I do not know the English word, Ruecklaufbremse in German) e.g. a Petzl Micro Traxion, a Garda know with two biners, usw., two slings and three biners are again the minimal equipment that work in all known systems. I repeat myself: Know your method and you will know what gear to take.
For anchoring it depends on the conditions: If there is blank ice, you need one long ice screw at least for the members at the ends. In case of a totally (and deeply) snow covered glacier your ice axes will be sufficient for T-anchors (make sure the shafts are T-rate, not just B-rated). Here you do not only need to know the method, but also the conditions.
Additional gear: Emergency bivy material (also covered in questions on TGO), first aid material, some kind of rescue beacon (assuming there is no cell phone coverage). As for helmets: Traditional mountaineering/climbing helmets (hard shell) are of little use if there is no danger of rock or ice fall. A foam helmet will offer some protection against bumping your head while falling into crevasses, but usually it is not your head that is mostly endangered in glaciers, as you fall with feet down.
