1. people say you need to show some of your past work on a kickstart video. is that something you need. also would just a video explaining the movie and your intentions be fine?
If you have previous work to show, that helps. If you have never
made a movie then you have no previous work so can ignore the
people who say you need to show some of your past work.
You might not even need a video explaining the movie and your
intentions - maybe just the written word would be fine. But if
want to put up a video explaining the movie and your intentions
you should give it a try.
2. if you are making a kickstart program, you need money. how do you get your actors who will be paid to be on the video and take some of their valuable time if you dont raise enough for the kickstart program or to pay actors.
You ask them. Almost all of us here have used - and continue to
use - actors who work for free. Of course it's always better to pay
actors and crew, but everyone knows that that isn't always possible.
So you ask people (actors and crew) to help you.
3. can a good DP also do all your editing? also will you need to get your DP assistants if he doesnt have a crew?
I know many DP's who do not edit at all. I also know many who are
good editors. It depends on the person, doesn't it?
Some DP's have a crew they will hire. If you are paying then you
should hire the DP and they will hire their crew. If you are not
paying then you are asking the DP to do you a personal favor. It
might not be a good idea to then ask the DP to ask their usual crew
to do you the same favor. But the best thing to do is ask the DP. There
is no "one size fits all" answer.