I want to use a new script but want to carry over my users. I am no MYSql expert but I think this can be done - how might I get started?
If you are running phpMyAdmin you select your database, click on the "Export" tab in the top, select the user table and descide what format you want to export it in. SQL, Excel, CSV, XML ...
Not true. You can still export it. And if you export it as CSV, for example, you can import the data in to the new table to the new columns.
Time will tell - I may have a custom script created so that would probably help since they can copy the same structure I think
Your new script can use your old data. Alternatively you can just create another table (or even a new database) and write a trivial script to copy the data from the old table (or database) to the new one.