Hi Piotr,
i do believe that you will no find the answers in terms of numbers because before a routers starts having issues in releasing IP addresses you will have a LAN service deteriorarion you cannot afford
However,
Answer to question number 1:
I have personally assigned for experimental tests 2000+ IP addresses with a single pool and i did not have any issue in the timeframe i have worked on it
Answer to question number 2:
On my production environment i have more than 50 pools assigned with less performing machines (ISR G1)
Answer to question number 3:
This number does not depend from the router but from the encapsulation you are using. Read about ISL vs DOT1Q max vlan number and their way to tag the frame. You will better remember why this value does not depend from the router.
About the question number 3, the 1941 will not have any issue to manage all the vlans that the trunking will need.
hope this helped
Alessio
