more brake questions

[67chevyguy]

Ok, first of all I used the search but after over an hour couldn't find what I was looking for. Few questions.

I'm doing a front drum to disc swap.

1: My ball joints are good and tight still(not original). Do I have to remove the ball joints to get the old steering knuckle off and put the new spindles on, or is there a way to do it while using my old ball joints? I have a ball joint press but I've read that there is no way to remove ball joints without wrecking them.

2: A guy at NAPA mentioned some people make a couple of coils in their hard line to allow some spring in the line. I've seen this in pictures but assumed they just had extra length in the line and didn't want to cut and flare it. Any reasoning behind this?

3: Can I use the power master cylinder from my 67 with a prop vavle for the disk drum set up? I bought it 2 years ago and would rather not replace it. Plus the disk brake kit I have is said to be a complete conversion kit for a 67 but did not come with a master, so I assumed I wouldn't need one.

4: I'm doing all new hard lines, the fronts should be 3/16 and rears 1/4, correct?

Thank you if you took the time to read through all that, and thanks even more if you can help!