Hello, I'm now scheduled to be taking over someone's domain name and hosting. Both of which will be under my control. The hosting will be transferred from Zen to Vidahost and the domain name to be internal transferred to my 123 reg account and then the owners details changed to mine. The domain is a .co.uk I just wanted to know what's the best process for all of this to happen very smoothly with minimal disruption.

Domain name:

The bit am more confused about is the domain name transfer. It will be done internally through 123 reg, which is easy enough as I already have an account with 123 reg of which already has a domain name there.

1) Will all the settings remain after the internal transfer or will I have to re-set those up?
2) What about changing domain details such as name of owner and address? Is that best done before the internal transfer or after? I'm aware a fee is involved via Nominet and that's fine, but does the current owner have to sign something?
3) How long does this take?
4) 'Cause it's internal all I have to change is nameservers and not any other tags? 5) The domain name has to be transferred through Nominet to new owner (me) and obviously also has to be done at the 123 reg side of things to - which order does that have to be or doesn't matter what order?

Hosting:

The current hosting is with Zen and I want to transfer it from his Zen account to Vidahost account.
1) Is it possible that I can purchase hosthing account right now under the domain name I want it to be, and setup all the email accounts, but remain inactive till the nameservers are changed and pointing to vidahosts? OBvioulsy the domain name i'll be getting is obviously still in use with the zen/123 reg setup so can i still setup the vidahost side of things? Thank you for assistance.

Domain name transfer will take Up 5 business days. And you will need to pay transfer fee for that domain name.
Web hosting transfer that is more faster, but you will need up to 72 hours for the DNS changes

Every domain name is purchased from a registrar. For many reasons people transfer their domain names. If you are transferring your domain name to another web host,transfer all files to your computer from your old host. Sometimes files may be stored on your host but not on your
computer, so doing this will ensure you downloaded the whole site. Keep a copy of your files on the old host, while you transfer to another host, so you won't experience any downtime of your web site. Open a new hosting account. Upload all files to the new host. Cancel the previous hosting account when you are satisfied with the transfer of your domain name to the new host.

Domain name transfer and web site transfer that is not the same. You need to understand that and web site transfers are more often then transfers of domain names.