Here are some numbers:

Combined Republic and Shuttle fleet:

190 E170/175
20 Dash-8
33 E145

Based on those numbers and a rough approximation of 10 pilots per aircraft (others more experienced please confirm this ratio), then eliminating all but the 170 fleet will require a total of 1,900 pilots on property for adequate staffing.

RAH's seniority list as of February has 2,109 pilots on property.