I just ordered the:
Samsung FlexWash 6-cu ft High Efficiency Front-Load Washer - WV60M9900AV
Samsung FlexDry 7.5-cu ft Gas Dryer - DVG60M9900V
Can someone confirm if this is compatible with SmartThings? If so, will it work on the classic app?
Also - do I need the Samsung USB dongle? Does it connect over Wi-Fi or Ethernet?
No, they will not work from the Classic app. If they are compatible, you would need the Samsung Connect app.
Do any of them work with the classic app?
Samsung TVs and appliances only work in the Samsung Connect app.
If I pair it with the connect app - can I use it with the classic app?
Any problems with using the classic and new app simultaneously? So use the new app (with the same account) for the washer/dryer and use the old app for everything else?
no
you can use both apps with the same samsung account.
yes, that is correct.
Do you have a smartthings or samsung account - that is the question?
I upgraded to a Samsung account.
time for you to install the samsung connect app and get familiar with it 
I won’t mind as long it doesn’t migrate my account and makes my classic app stop working lol
Sorry to revive this topic, but I need a new gas dryer and looking to see if this will work before I buy.
Once I get it setup through Samsung Connect, will the object appear in SmartThings graph IDE? All I really care about is when the cycle completes, I really don’t care about starting it or stopping it or anything else. All I want to know is, is the object addressable in IDE, and if so, what attributes show up for it. Most of my automation is done in WebCoRE and as long as I can read attributes off IDE, it will meet my needs.
Thanks!