This may not fix your problem, but you will likely run into this too.
Be sure to enable swap on the t2.micro instance. If you don’t you’re going to run out of memory catastrophically sooner or later. How to enable swap -Discourse Meta
I’m running on a t2.micro (web only install) with db and redis running on separate boxes (RDS and Elasitcache) and I’ve run out of memory on the t2 instance.
AWS DOES NOT monitor your memory for you, and when your process overruns the amount of available memory it quits in all kinds of weird. These are strange spurious errors (or no error at all) that are hard to track down until you watch your memory use and see it go near zero when the process gets wonky.
Another thing to try: Stop your instance, adjust the instance size to a t2.medium, boot and try again. If everything installs fine you can stop again, downgrade to the t2.micro and boot again.