You can easily cut these tubes with a pipe cutter... Takes 2 min and give it a light sanding....

Yes

You might have 2 cut a little off pretty easy with hack saw . I bought one for torpedo keg and its was a bit long i cut off a bit works great.

I bought it to fit a pin lock keg. It was several inches too long but that was expected. I used a standard plumbers copper pipe cutter tool to trim to length and has worked fine. Ball locks are taller so the added length should be good but you may have to trim. The threaded posts are similar enough that I expect it to fit fine from that perspective. You will need to provide new o-rings.

It will fit but the issue is the length of the tube. Depending on the keg manufacturer the tube may be too long. You don't want to have to cut it. If the tube is too long the best solution is to carefully bend it with some technique to avoid kinking the tube. I used this tube on a torpedo keg and it had to be adjusted five times until I got it just right. (Each additional application of bending pressure was a micro adjustment. It's a nice challenge and perfectly doable. Even if you are replacing a straight dip tube with this straight one you may have to bend a gentle curve into it to make it just right.