A few questions came to my mind about your project, I hope we can discuss it.
1. About ToS and data privacy:
a) when someone fills in a form for proposal, you need to handle their data, how do you manage that? Because you have to give a company who handles this in the ToS, so you put the company that will be your affiliate partner and always update it - if it changes, or you create your own company and you state that you "resell" the data to 3rd party?
b) if its a possibility to make a call on your site, you own a dedicated phone number for this which you hand over to your affiliate partner or you always post your partner's own phone number on the site?
2. Pricing:
a) I think there should be a basic price which cover the monthly fees (website admin, web hosting, cost of ppc campaigns, phone service - if you have your own [see 1b], content creation) right?
b) and the second part is about leads - I assume you charge for the leads who clicked on either the phone number CTA or filled in a form on your website, because that can be easily tracked, and if your partner doesn't able to fulfill their needs or expectations, that's not really your problem? Since your ads worked because they ended up on your site, and since they have made contact, your website worked also.
Looking forward to your reply

Cheers
PS.: I hope my questions don't sound silly, since this is the first time I have seen this business model, I try to dive deep in it more.