They said they'll start with a mass market device. There were rumprs of an exotic enthusiast device coming out, but those are just rumors.

Perhaps if Jolla doesn't come out with their keyboard phone some other OEM would do it.

And regarding whether or not it's a copy? Who cares? Does it actively try to imitate a specific mobile OS (see old Touchwiz versions vs. iOS)?

It doesn't. It takes concepts from other mobile OSes, but that's what all nee technologies do. Incremental improvement, much like how many browsers followed suit once one went tabs-on-top.