I'm thinking I can just write a simple letter giving notice that the lease will end at the end of 12 months letter style without citing any specific reasons. 

I can't add a lot of advice to the specific strategy, but I would urge you to focus on simplicity.

I also practice as a Realtor because I enjoy it and it is extra income.So as an investor, your options are to get your RE license and have access to a lot of tools and do the research yourself (therefore you're paying with time, energy and a little money) or you work with a great realtor/investor in the specific market you're looking into.

Podcasts on the way to and from work, and read a book right before bed, maybe even squeeze a few minutes into browsing some specific topics in the forums.

If you wish to network or ask specific questions about your local market, you can go to your local real estate forum and discuss with investors from your area: https://www.biggerpockets.com/forums/86-local-real-estate-networking 5.

Looking for suggestions on any specific building materials, fixtures, accessories, furniture, and tech for a STR.  

Our letter specifically stated no appraisal necessary.

They are more like an investment club / provide coaching (I am guessing for a fee) but I as a sponsor was told we don’t get any fee or have to provide any kickbackSomeone I know who is a member noted they do not act as investment advisors or provide investment advice nor are paid based on specific investments but I am sure someone can Confirm this I wonder how they get paid then.. ???

Savvy buyer's agents look at stats like sold price to list price ratio trends and watch specific properties to see what they sold for compared to what they were listed for to really understand the market and make offers accordingly.

Any tips on what to screen for specifically?