1. yes you can use it in non-production envirnments for testing and development
2. yes before it goes live as a production site you should purchase another license
Note that these answers apply to sites using separate installations of mojoPortal. A single installation of mojoPortal can host multiple sites and a Single Installation License of Form Wizard Pro can be used in all sites within a single mojoPortal installation.
However I don't generally recommend hosting multiple customers in the same installation (though some people do that). I recommend only hosting the sites for a single customer in a given installation of mojoPortal because it makes things easier if your customer later wants to move to different hosting or requests a backup of their site. It can be aproblem for those situations if there is data for multiple customers in the database.
Hope that helps,