If you return right after you leave Helgen, you find corpses and a few throwaway items. If you return later, you find bandits. Either way, I've never found what OP highlights.
Keep trying I don't think them not being here is decided at the start of the game but just the usual collision issues these games have had, maybe something alduin does. A in game month at most. I don't think you not being able to collect them you make them not respawn because it's more of a cell reset anyway. Ie. I went shortly after the start, still on fire no bandit found 3 of the 5 that are set there, went back in a week, bandits had spawned fires out, potion and chest added no drink, passed though an in game month later and decided to have a look, the bandits where back and so were all 5 of the bottles. They could not be there again I guess though for the same reason entering your house things go flying about and mounted weapons drop though the world.
I found a couple of survivors wandering around asking for gold.
Not intended to be form helgen are they? just a random farm that has been attacked.