Advice On How To Best Structure the Plugin

HI all, just trying to figure out if I can make this plugin work for my purpose.. I think it can, but I am not too bright and can’t figure out when to use custom taxonomies, tags, etc.

I want to create a web site directory where businesses can add their own listings.

I will target mainly 2 groups, let’s call them Agents and Appraisers. A listing can NOT be both.

-Is there a way to have 2 different signup pages, one targeted for Agents and one for Appraisers?

-Can I allow Agents to be FREE but charge the Appraisers? How do I distinguish in my setup?

I want a website visitor to be able and browse either an Agent or an Appraiser directory.

-Same question as above, except from the person browsing stand point? How do I create 2 distinct directories?

I need basic info, such as address, city, state, zip, phone, web, etc. for each category listing.

-Can they be slightly different for Agents and Appraisers?

Would it be best to use WP Multi Site?