When juggling domains, I take it slow. It takes time for one change to take effect, then time again for a re-change to take effect.
While it's too late now, I try to wait 24 hours before re-doing a change to give the first change time to propagate. Re-adding doesn't mean that DreamHost keeps your old domain info. The webserver also needs time to catch up as it's hosting virtual domains via its own configuration.
I see two choices: Wait 24 hours to see if your changes happen. If not, delete what you had, then wait another 24 hours before re-adding the domains. Or contact support to see if they can clear things up.