Ten-X is a pretty popular platform and as such you will find good experiences and bad.As with any of these platforms, the properties may have little competition or might face a lot, depending on the market on who shows up to bid (online).I have not used it in years but had bid on some stuff.

Professional photos will take your listing to the next level, so do not try to take the photos yourself unless you have the talent required (i.e professional).Once you have furnished the property, uploaded the photos and created the listing; you are good to go on making your listing live on the Airbnb platform and putting your arbitrage strategy to work.

Online content is pretty good, and they have classes M-F you can sit in on and listen through their "eXp world" online platform. 

Those who invested on this platform are having a sobering realization: it's backed by nothing.The institution, the assets, and their investments, which many put their livelihood into, only have a foundation of speculation and hype.This is the first of many.

I have thought about making some mock post to put on social media and other housing platforms to better gauge the demand.

Syndication has grown so much in the last 4-5 years thanks to many equity raisers using YouTube as their platform to help people understand syndication.

If someone figures out a way to get AirBnB response without the costs to the hosts or tenants, then AirBnB will go under but until then the platform serves a purpose that people are willing to pay for, directly or indirectly. 

If so, you should also check out VRBO to see if there are any nearby listings on that platform. 

Any suggestions or advice on good platforms for Direct mail campaigns?

I'm familiar with wordpress and shopify, but I imagine there's maybe a 'direct' booking site platform out there we can host on our own domain?