Hi, thanks for the response! (Sorry I didn't see it sooner, somehow I missed it.)
To be more specific, "domain.com" in your example is amandarosskincare.com and "mirror.com" is amandrossskincare.com (double 's' vs. triple 's').
I had already added myself to the FTP access for domain.com but got stuck when I realized that mirror.com could only be reached if the www is typed in front of it. HOWEVER, that doesn't seem to be the case anymore...I just typed both domains in my browser and they both render whether the www is in front or not. (?)
This website is currently not a Wordpress site, but it will be changing to a Wordpress site soon. You mentioned settings changes would be required in that instance. I will need to get straight on what address to place in the website address and website location settings in WP General Settings. I'm assuming those are the ones you mean. If I leave the domain settings as they currently are, what url would I place in wordpress settings?
Please feel free to check the dreamhost settings for these domains. I have not used Dreamhost before so not too familiar with your set up and I have not used mirror sites in the past.
Your help is appreciated, thank you!