I'm thinking about changing from Telecom to Vodafone, as my usage has changed, and Vodafone have the plan best suited for me. I would still like to keep my old 027 number though.

What process and costs are involved in setting up my old 027 number on a Vodafone phone?

Also, for people that text me who are 027, will their texts to me still get treated as a text to an 027 phone? How will they know the difference?

What about Telecom's favourties plan? If I'm someone's "favourite", will that still work?

And freedom? I have freedom with my parents, will this still work?