No new pilots needed for the foreseeable future. (Except maybe a few new second officers from their own flightacademy)
But to answer your question:
Cityhopper and mainline are on only on paper different. Pilot pay is dependent on fleet, seniority number (from both companies combined) and some other factors.
Mainline and cityhopper have the same CLA so difference in roster is depending on fleet and not so much the company.