Bob, there are many safety and code issues with stairs and a lot of different ways that they are constructed. I would suggest that you look around in the related posts on the site and you might get some idea as far as maintaining the same rise for all the stairs. Remember to look also for handrail height issues and code questions surrounding those. After that, you might look for another project and leave this one for an experienced pro or go to your local government office that handles building codes and ask them for a copy of the applicable parts of the code that they use that covers this and any tips that they can offer.
You might want to consider that if someone does take a fall on your stairs and gets hurt, your homeowners insurance may not cover you if you have made changes that put you out of compliance.