Yes, yes, and yes. The calipers on the disc brakes differ so much from the OE drum cylinders that the valves are IMPORTANT. Now, without the valves there will still be braking power, but much less so. With the new soft brake i
lines now available, the fitting will not be difficult. I would buy the shortest possible and keep the professional ends.
New brake lines, for certain. When I discovered the new line material, I removed all the steel lines I had made and replaced them in two hours. Again the new soft lines are the only way to go. If you buy a variety of lengths, you can place where fits best and use all factory ends. Lots of way to shorten a line that is too long without having to cut it. That is a cosmetic decision.
Good luck. This shows steel lines which I replaced.
luck.