ZFS Can FreeBSD read Linux OpenZFS format?

If I put a Linux formatted OpenZFS HDD into a FreeBSD system, would I be able to mount the drive as if it were a native FreeBSD ZFS drive?
Most likely, yes. So long as your FreeBSD version supports the same ZFS features, then the pool will be importable. Linux tends to lag slightly behind FreeBSD when it comes to ZFS features.