They have a payments 3rd party website, but it's hard to find the link from their main website. 

Buildium's 3rd party will issue the 1099 to the PM company.

Working this backwards, what I see is a 3rd party trying to benefit from another’s house via rental cashflow, My only business is 30+ years as probate estate and trust lending in CA.

So, all parties over 18 need to sign the lease.If they are going to sign the lease, why wouldn't you screen them?

Most deals I work, I find that the most inexperienced party in a real estate transaction will end up losing 4-10% of the value of the home in the transaction because they don't know what they are doing. 

Post Dodd Frank sellers have continued the same bad practice of selling houses to occupants with financing at selling prices that are way high, can't be justified via any type of 3rd party valuation (appraisal, zestimate, tax value, even recent sales in the same area).   

I appreciate it.Aside from the option to be added as 'additional insured' they have the option to purchase a  "ProtectionPlus Bundle' from Surevestor, which includes several things like protection against eviction costs, wilful damage to property, over a $1 Million third party liability protection, loss of rent protection for 25 weeks etc.This is $50/month.

Does anyone have a good effective 3rd party mailing company to send mailers direct to seller?

Their company is pretty great at not responding to their communities people , not following local law yet alone their own lease agreements The uptick of lot rents I get it it’s business but also driving out affordability for people which again it’s a business so some may say that part is just the territory , but not following lease agreements , hiring poor management and then doing nothing about it when it’s escalated is a reflection on their business aswell   best of luck. 

Additionally, involve a real estate attorney to ensure the transaction aligns with legal requirements and protects both parties’ interests.