if your dad has the pipe cutters, have him help you.
I used a hack saw for many years, worked fine too.
just becarefull you don't cut too much or you will be buying new bars.
as for your seatpost, that is up to you. I'd leave it long until you know exactly where you want to run your seat. if you decide you want to raise it up, you can if you don't cut it.
cutting it won't help you be any better of a bike rider but spending time on your bike will.