That is enough to play at the basic level. And really the only must haves in paintball. I can almost guarantee a majority of people probably played a lot of their first few games with just those 4 things.
After that I would personally say a good pod pack and pods. You will probably want to have more paint on you no matter what game type you are playing, or whatever your marker setup is. Even people renting find the need for a pack at times. Although, if you play a style where you find yourself only needing what is in your hopper, I would stick with that until you get burned out playing that way. Not only does it mean you don't require a pack, it will save you money on paint.
A swab is a good idea, or any marker maintenance related accessory for that part. But that list is created as you start playing more and figure out what your marker needs.
From there I think it's really just personal preference/need and mostly related to soft goods like cleats, boots, pads, pants, gloves, jerseys, headbands etc.
But again, if I was forced to buy the must haves for a game tomorrow I would go with the first four listed.