Hey Jochi,
There is a Wainman Hawaii Riders Group on Facebook. You'll find good reviews and tuning tips there. Just search... Wainman Hawaii Riders.
to answer your questions:
1) I have not found the need for the Mini 5th line. The kites depower SO much just with the throw of the bar, that even in Suicide Mode, the the kite drops powerless. If you do want to use it, run it up through the center of the bar and attach to the re-ride loops.
2) I would never use a full 5th line unless the kite couldn't fly right without it. More drag, more to tangle, and no way to undo an inverted line on the fly. This kite is not meant for 5th line. The little loop at the center of the leading edge is for attaching your kite pump during inflation.
3) Do not self launch this kite like a C-kite. It launches like a bow and rolls very easily. If you are on sand in open safe area with lots of downwind room, place the kite on the sand with the nose pointed mostly into the wind (normal kite on beach position). A little sand on the canopy center will keep it in place until you tense the lines up. Walk perpendicular and just a little up wind of the kite, pull on the furthest wing tip, and it will catch the wind rotate and launch. If it starts to tumble or stall, just push the bar out and continue to steer. The safer way is to unwind your lines in the water, push the kite away from you, and do a classic water launch. (just pull on one of the side lines)
4) Self Landing is easy with the rabbits. Just attach your leash directly to one of the red center line re-ride loops. Bring the kite down on the side of the window (the opposite side from which you attached the leash), and unhook. Smartest to do it on water or in a wind shadow to avoid any tumble down wind which could damage the kite.
www.skybanditz.com has all the Rabbit Gang in stock with Free DHL shipping.