The Crossbow 1 had heavy bar pressure. I didn't find that a problem - having windsurfed and it can be a bit of a help at times when you are learning, but it does tend to teach you bad habits like pulling on the bar for something other than sheeting the kite.
There is no need to reduce the pressure, but there was a bridle mod which I did to my Crossbow 1 and it did reduce the pressure but made the steering slightly more vague.
Its a mod where you really need to know what you are doing or you could make the kite uncontrollable, so it would need to be done by someone who understood all the things that can go wrong. It involves getting a replacement length of bridle line made of exactly the right length of 3mm dyneema to replace a pair of lines, and fitting a pulley on the end of another line.
There are diagrams about it here.
kiteforum.com/viewtopic.php?t=2322178&start=30Like I said, it doesn't need to be done - the Crossbow will be just as suitable for a beginner without it.
It is worth buying a new replacement inflation valve as it makes it easier to pump the kite up. The original valve had a lot of back-pressure.
You will just have to use the original leash system to a single front line. It would be possible to rig a through the bar system but it would probably cost as much as the kite cost you to do it. Most leashes will not reach it so you have to put a small extension line with a ring on the bottom of it, onto the flagging ring of the kite.
The carbon bar was standard.
I moved the stopper cylinder up the centre line out of the way when learning, - or you can reduce the force to click the stopper into and out of position with a bit of light sanding of the sharp edges of the cylinder on the centre line.