i am not related to the site , i suggest you contact  the owners of the site to find out your questions , but i will try for you

a. Are the original listing prices genuine? If so, are they independently verified, or is it up to the agents to input?
this data is avaiable to anyone who watches the market and tracks prices – however i do believe it is agent inputed

b. How much is paid for listing the property on the site?
free for agents to  signup and list  properties if you went to the site and click on agent sign up you could see that

c. Why are there so many google ads on the site? Makes it look a bit dodgy.
Sites list google ads as a form of revenue –  normally  so they can keep their membership fees lower.

d. Who are the people behind the site? On the 'about us' site it doesn't mention names.
You need to contact the site directly for this answer their is a contact us page you could have used

Also i was only posting cause i thought it was interesting and useful for uses  of this site would be interested as i have not seen this site before ….