FWIW I certainly hit storage space in some boring ways - I didn't have a good logrotate setup so I almost ran out of disk, and I sent my box-check logs to Redis and had to set something up to offload old logs to disk to not break Redis. But neither of those were very big deals - pretty interesting to have a problem like this where storage just wasn't a meaningful problem! That's a new one for me.
And yeah, thinking about bandwidth was such a headache. I was on edge for like 2 days, constantly checking outbound bytes on my nic and redoing the math - not having a hard cap is just really scary. And that's with Digital Ocean, which has pretty sane pricing! I haven't used the popular serverless stuff at all, but my understanding is that you get really gouged on bandwidth there.
(also yes, lua-in-redis is really incredible and lets you skip sooo many hard/racey problems as long as you're ok with a little performance hit, it was a joy to work with)
I think you hit every type of interruption and point of failure, except storage space, and it is great to see your resolutions.
I wasn't aware Redis could do the Lua stuff which makes me very interested in using it as an alternative state.
As for the bandwidth - one of my biggest gripes with cloud services as there is no hard limit to avoid billing overages.