any ideas on what type of governments I should build (outside of my homeland) to best reflect a true roman "republic"? Should I solely use type III and four to represent the autonomous nature of the provinces?

ALSO

should I only keep FM's in Rome (to act as a senate, and only use FM's in province capitals and leaders of the army (consuls and praetors).

I only ask this because I know at some point, most family members gain the trait of "Senatore" and I wonder if I should keep all of the Senators in Rome instead of stretching them thin across the republic.