Default Question about roms... please assist

Ok so i have a Haipai i9389 which as I am aware is a clone of the galaxy s3. I have a couple questions

- can I put any galaxy s3 rom on it or only one tailored to the clone phone?

- I do not have an sd care at this time so I use the sp flash tool for my last rom and I downloaded another rom but it did not have the scatter file like the first one did. Is there anyway to make the scatter file or does it have to come with it to use the sp flash tool?

I am wondering because I downloaded a few roms but none have the scatter file so I cant use the sp flash tool as far as I know and sorry i am new to this.

lastly if I can put other roms on my phone and such what rom would you suggest for my haipai phone. Im basically looking for a stable fast running low battery using set up.

thank you in advance for any advice and help on this matter