Hello Nishit thank you for your message,
1) Will functionality purchase all Numbers match with the admin choice? – Yes only site admin will regulate and set up all rules which numbers to purchase and those to reserve.
Currently Intelligent allow numbers reservation for the limited time that is set at Intelligent interface.
2) Please use current admin emails that associated with Voip users for purchasing numbers. Admin emails are mentioned in notification settings (where you put developer5…email)