I am pulling together a business plan as I am interested in partnering for the first one or two properties and want to present potential partners with enough clear and accurate data that they can make an informed decision.

Here's my data from Upstate NY. 

Very helpful and I will definitely reach out to a professional to ensure everything in the correct order. 

Are there any private forums/communities for SFH investors to share data on their investments anf feedback on providers/PM's/markets/etc? 

Assuming that your agent is good, it'll also ensure that your rent is inline with market, tenants are vetted as best as possible, and leases are done on the up and up. 

Feel free to reach out if you want to connect and get more data on the different Austin markets.

What are some of the strategies that out of state investors use (particularly in DFW area) to ensure that we are picking up great deals in neighborhoods where rentability will be high for years to come?

I understand each coop has its own rules so it could be possible to rent your coop unit but how can I filter my search to ensure I can use a coop as an investment property?

All the data online and pictures can only tell you so much. 

You'll also want to ensure you have a good property manager to look after the upkeep of the property if you are not there to notice anything deteriorating or which may need attention.This article goes into a lot of the considerations about whether to form an LLC or not: https://www.mmpph.com/wp-content/uploads/2019/04/May-2019-newsletter.pdfCreating an LLC in California would cost you a minimum tax of $800 every year.