Preparing Installation

Hi everyone:

We have a running website which is old but needs to be up until the new Website designed via wordpress and the template LawBusiness by cmsmasters. The new Website also Needs to be featured in three languages, either sub-directories or sub-Domains (I have no idea what is best). Therefore, need to install multisite on wordpress.

Q1: Can I install and start working on the new Website (WP and template) with a fictive domain-Name while the old site is still running, and when I am read with the new Content upload that?

Perhaps there is someone out there who can help me with the wordpress-set-up. I would greatly appreciate it.

The theme LawBusiness has not yet been downloaded/purchased as there are still questions about what Needs to be done in which order.

Thanks a lot ?n advance for your support and reply.
Best, Michelle