I have used avail.co in the past with great success but it appears this software and others no longer market on zillow which I know to provide a lot of leads in the past. 

Personally too, I look for the best quality and always provide that to all my clients.

If you decide to revisit STRs, you might want to explore properties where you can project expenses independently, such as using local STR forums or online tools to estimate maintenance, management, and occupancy costs.For networking and strategy-building, you might find local meetups or groups beneficial.

I have a template that I provide and they can either complete the template or just give me their documents and I'll complete the template before prepping the taxes.Self Managed, High Volume, Very Organized - these folks keep up on their activity. 

I used to provide detailed answers to DMs, which are private and help only the requester.

You may want to make an introduction between your CPA to those 2 colleagues.The CPA can go over their services and pricing to your colleagues.I partner with many people on real estate deals - It never gets to a discussion on whether they do their own tax return or hire a professional.If a partner mentions he will provide capital - does he provide the capital on a timely manner.If a partner mentions he will find deals - does he find many deals and provide an analysisIf a partner mentions he will manage a property - does he manage the property well(find tenants, collect rent, communicate with contractors, etc)

It is also providing great experience for them so win win.   

I'm looking for the cleanest & most visible way to access payment history, see amortization schedule, tax documents, etc- much like bank softwares provide. 

(Even went beyond the second page of Google.)I have an investor who wants to partner on a deal by providing a loan for the down payment.

I can’t think of an expensive subscription that doesn’t provide an app.