Best WP theme/site builders for an effective Community/Directory website?

Looking to get the small touristy coastal town I live in Online - in all aspects literally Online Marketing is still a very new concept here and hardly no one is doing it but businesses are very open to it.
The website will include a business directory both for corporate and small businesses such as electricians,plumbers etc local events(what's on), places of interest, leisure, restaurants and more. The idea is to make it a community go-to website to find the usual frequently searched for info in any city/town.

Monetization: All listings will be initially done for free with an aim to generate significant traffic, then monetize via premium classified ads for businesses that want to stand out from the competition.
On the back-end of this I would also hope to interest businesses already paying for ads with other offline marketing products once we build social proof. How else can I monetize this or maybe I should ask how can i offer even more value to the users?

I am sure this is by no means a new business model, so I am keen to hear the advice and suggestions from the experienced warriors who've been there and done it.
Any suggestions of most recommended platforms/WP themes or site builders that will best suit this business proposition?
I most likely will outsource this but I am sure it helps to be very clear of the whole structure of such a project in the first place.
Warm regards,
Rose