I have (almost) the same problem (as well as just having installed SD3. In answer to your three questions –
• There’s an EZDrummer folder in Application Support, but its an alias to my data folder on another HDD
• I have moved the content folder
• Applications/Toontrack shows the attached screengrab.
PM says that SD2/3 are installed and up to date. It says that none of my expansions are installed (which they are, and all working). It prompts me to update SD3 midi, which I do but nothing in PM changes….