I just switched to the subscription photography plan from my stand alone version of LR, from what i can tell I really only want to use LRClassic and PS. Can I just uninstall or delete my original LR and the other LR that I just downloaded ?
First, make sure that you have installed the Adobe Creative Cloud Desktop App on your computer and are Logged in to your a/c. This application allows you to manage all the App that you are allowed with the Plan you have chosen. If you have subscribed to the Photography Plan then your Adobe Desktop App should look like the screen capture. It may show the previously installed applications there.
You can install the apps you wish to use and you can uninstall earlier apps after you are satisfied that the new apps are functioning properly.
I would like to add that I use LR-Classic about 95% of the time. Where I do find LR beneficial is when I take any photos with my iPhone either with it's camera or via LR-Mobile's camera (same camera just different access point) but those will be synced to your desktop computer's version of LR. So, if you have the hard drive space, it's a nice added benefit of something that you already own.
In addition, if you have LR-Mobile on your phone, you will be able to show people the images in your LR-Classic Collections.