What you want to do is easy.
What I would do is this, point your new domain name to the same nameservers that creative-echoes.com is pointing to. Next fill out a ticket to support at
http://desk.surpasshosting.com and ask them to do the following:
1) Change creative-echoes.com to lela-grace.com.
2) Point creative-echoes.com to lela-grace.com.
With this setup, they can type either lela-grace.com or creative-echoes.com and automatically pull up lela-grace.com.
This is an easy two step process for support to do.
For question 2, just order new hosting using the new order links, I believe all new accounts have to be in the new billing system. At one point, I know they mentioned they were going to eventually migrate all accounts to the new system.