If the ring/wire size is the correct on those crimp connectors they should be fine, best way is to crimp, solder and shrink tube them.
Although when I did mine I believe I just crimped and shrink tubed them , haven't had any issues.
If removing the master cylinder allows you to treat a rusted area that you wouldn't be able to get to otherwise, then probably necessary.
You'll need to remove the brake lines coming from the distribution block before unbolting from booster, brake fluid will eat through paint so
be careful to wipe up spills quickly. System will also need to be bled when reinstalled , probably not a bad idea since you most likely
don't know the age of the fluid.