I’ve used elastic beanstalk w/o RDS or SQS. Packed binaries and config files into a zip archive ( per beanstalk manual ),exposed services through Procfile, set load balancing and HA options and pretty much it. Has been very stable.
Watch out for misconfiguration (e.g. kinesis message size can’t exceed 500 events ), otherwise check the logs, run a load test and you’re good to go. Will take 20-30 minutes or so start to finish.