Upload & Sell: On
One other consideration. If you upload directly to FM there is a maximum file size limit. From time to time Fred has increased it, but I think it may be 650k. You can check the Upload page for restrictions. I typically export from LR as jpeg with longest edge set either to 1000 horizontal or 800 longest edge, max file size 600K, sRBG. Since you have the upload subscription you have the option of adding mat and frame, EXIF after upload.
Havent heard anything about a direct export to FM plug-in.