Multisite testing process advice

Just reading up on Multisite recently in relation to possible using the likes of JobRoller and other app themes and have a few queries:

1. For testing offline will Multisite install ok in Mamp on mac?

2. I currently have a total non WP website setup with a homepage news blog (index.shtml), a listing directory https://www.website.com/directory, and a jobsboard https://www.website.com/jobsboard

any advice as to the best way to install live test WP multisite at the root and maybe create https://www.website.com/directorytest and https://www.website.com/jobsboardtest and then is it possible to switch that later when ready to go live to the non-test names? or is there a better way to do this? and would changing the names later mess up multisite?

would I need a htaccess file change in the main root to keep the test index.php from showing as the HP until all is ready to go live?

Ideally I’d be planning a WP news blog on the HP, a test of JobRoller to replace existing jobsboard and perhaps a basic WP based directory until a more advanced app theme like Vantage or other comes along.

The advantage of multisite being users only have to register once across directory and jobsboard.

Any advice much appreciated.