The Flex and Mini TTl give no advantages on a Phase One 645DF with leaf lenses, in fact they are worse/ slower than Multimax or Plus IIs. I know as I've spend days playing with all the combinations in a bid to get my Phase DF/ leaf lens/ P40+ back to sync wirelessly at high speed.
Yes, it has the latest firmware so works perfectly if you hard wire.
With normal Skyport or Plus II, it syncs up to 1/400th. After that, if you use Multimax set to "Fast" it syncs up to 1/800th but you lose about a stop of light.
If you use the Canon Mini and Flex, you have to use the latest firmware and select "standard" triggering mode. This eliminates all the adjustable sync timing they have and puts them back to like standard Plus IIs. In fact, worse than that. They only sync up to 1/320th at that.
I have been in contact with Pocket Wizrd (the owner emailed me in fact) and I know the boss of Elinchrom who are also working on something, but nothing will sync a Df at higher than 1/400tb wirelessly properly yet.
The Cyber syncs are the same as PW Multimax on Fast, but rthe Profoto is marginally faster.... but not by very much at all. This info came from Jim Clark of Pocket Wizard so I haven't tested it. But he knows his stuff.
Hope that helps
Adam