more opinionated advice: ElasticSearch and the entire "ELK" stack (Logstash+ElasticSearch+Kibana)is awesome; but don't use it as a primary data store. It's not meant for that even though some of us are using it as such.
and make a more than a mental note to cancel the domain name if you don't use it in a year's time. It's the re-occuring domain charges that really get you in the end. (no pun intended).
A container can expose ports that the application is running on to the host. For instance, one of my web server containers might expose 9000 to the host. You could access 9000 directly from the host or you can setup nginx to forward 80 to 9000 if that's what you want. Something like that.