If customers are migrating over on the same network i.e. O2 to Bluetone O2 then this should be a seamless transfer with no down time. If customers are changing network i.e. porting from O2 to Bluetone Vodafone then they may experience some down time on the day of transfer but services should return to normal within the same day.
Yes you can, regardless of network choice we can easily facilitate a move from network to network without having to issue new numbers. If a customer has a requirement for a different number though this can also be achieved very easily.