Hi,
I hope you had a lovely weekend. 
Thanks for choosing our products and for providing all the details!
As Chris mentioned, themes are mainly responsible for the design, while the functionality is provided by plugins. In other words, you can think of the theme as the visual foundation of the website, so the choice of theme mainly depends on whether its design fits your project.
Regarding the functionality, you could consider the following approach:
You can create a dedicated Brokers page [e.g., Experts – ExpertHive] that is visible on the frontend [go to WordPress Dashboard > Pages > Add New, give the page any name you prefer, and publish it. The page content can remain empty. Then go to HivePress > Settings > Hosts > Hosts Page and select the page you’ve created] and add it to your header or footer menu [go to Appearance > Menus and add the page to your header or footer menu]. This would allow users to browse available brokers and contact the one who best fits their needs. You could also add a Top Brokers block or something similar to the homepage to highlight selected brokers or simply showcase some of them: How to customize pages - HivePress Help Center.
If you want brokers to have an active plan before they can publish their profiles/listings, you can use the Memberships plugin.
While Memberships doesn’t have a specific option to charge for registration itself, you can achieve a similar flow by restricting profile fields behind a membership plan. For example, brokers could create an account and start filling out their profile, but they would need an active plan for the full profile information to become available to users: How to block vendor fields without active plan | Loom. This can effectively work as a paid broker registration.
If the house purchase is handled directly on your website, you can configure the buyer’s fee or commission in WordPress Dashboard > HivePress > Settings > Users > Buying. You can set either a percentage or a fixed fee, for example, to cover transaction expenses: How to set up commissions - HivePress Help Center.
You can also charge brokers or house owners for sales using WordPress Dashboard > HivePress > Settings > Vendors > Selling, where you can configure the commission or fee applied to vendors.
Additionally, custom commissions and fees can be configured individually on the vendor profile level when needed.
By default, only administrators can change the author of a listing from the WordPress dashboard. However, there are a couple of ways you could structure this workflow.
One option is to have users choose a broker first and communicate with them using the built-in Messages functionality. Once they agree to work together, the broker can create and publish the house listing from their own account.
Another option is to use the free Claim Listings extension. In this flow, the house owner creates the listing first. Once they agree with a broker, the broker can click Claim Listing on the listing page. You, as the site owner, can then review and approve the claim, after which the broker becomes the listing author.
A quick note regarding the strings: you can change or rephrase any of them using the free Loco Translate plugin: How to change any static text - HivePress Help Center, How to translate HivePress - HivePress Help Center.
If you’d like guidance on implementing any of these features, please let me know and I’ll be happy to help!
P.S. You can also check this playlist: How to build a vacation rental website like Airbnb or Booking.com - HivePress Help Center