MongoDB instance for production
First Question: In order for this communication to be secure, would it be a better idea to use HTTPS port 443 instead of that basic TCP port 27077 , then disable the HTTP interface in the mongo.conf file? Is that enough to make the communication secured?

--yes enough.As port and ip security is there apart from that you can use iptables for more security. As currently you are just preventing mongo attack only.

What would be the best way to always make sure the mongo server is always responsive or running? (for example if the server was rebooted, I need to make sure that the mongo is still running) or (to avoid mongodb.lock file) because I had that issue before.

-- if you are running it as service then lock file issue will not be there.in case you are using directly from bin then put it in rc.d simple.
advised you to create a script to check your server status and configure alerts accordingly.

BACKUP: As you are not using replica then simply mongodump will be advisable but you can also start your single machine as replica means without any secondary you will have oplog for incremental backup.
You can start instance with replset option or change in config file.
then below command.

&gt;rs.initiate()


it will give you something like :

{
    "info2" : "no configuration specified. Using a default configuration for the set",
    "me" : "machine:27017",
    "ok" : 1
}


check one oplog.rs will be there in local database.