I will answer your first question.
In terms of the number of bases and the personnel needed, it all depends on the source of the threat, the magnitude and the number of missiles. Right now, as mentioned, the system is designed to defend itself against rogue missiles launched by rogue states. So the system is not intended to defend itself against large-scale attack. Countries that represent such a threat, especially North Korea, do not have missiles of that range. At present, there are no such missiles in Iran.
I think the existing facilities are sufficient, but that might change in the future.