"Or, I guess I could post a question on a tax professional discussion board asking if anyone already knows what the consensus is, so I don't have to do this myself?"

You asked on a software forum, you asked Peer users, for Lacerte.

You might find a Dept of Revenue Association community that has all State DOR participants, and ask them. After all, you don't seem to understand that you have been given the info you seek:

Which states accept which forms as amended and efiling, but the software provider has to provide the forms and access to do it. So, asking "will other states participate" is a meaningless question, because we already proved it's more than "a handful."

If you would like me to do your personal research, all you have to do is hire me.