Many questions before upgrading to newer MBpro

[STeeleMarine]

I work overseas, and will be selling my current MBPro to a colleague before my departure back. I have a new MBPro sitting at my house waiting for my return, and I want to re-install all of my old data on my NEW computer- without having the old computer on hand. Can I do this by backing up all the data on an external HD, or is there more involved? For someone who is not very Mac Savvy at this point, I could use some help in "baby stepping" me through the process. I frequently run Time Machine to an external HD, but want to make sure of a few things prior to the handover:

How can I keep a copy of ALL my Email (both sent and received messages)? This is SUPER important!
How do I transfer my photos and music? I think this is more straightforward, but thought I would check as well.
How can I guarantee all of my files, and data can be securely wiped or trashed prior to the handover?

Thanks in advance to any and all who can assist!!

 

[Makosuke]

Since you have an "empty" MBP at home with nothing on it yet, this is particularly easy. One method, which I've used plenty of times:

1) Get an external drive at least as large as your current MBP's internal drive.
2) Connect the external, format it as a Mac volume using Disk Utility, and use the free Carbon Copy Cloner or another drive cloning program to clone the entire MBP internal drive to the external.
3) Check to make absolutely sure all your data is on the external.
4) When you get to your new MBP, connect the external and use the Migration Assistant (it will run automatically on first boot, or you can launch it from the Utilities Folder) to transfer everything "From a Time Machine backup or other disk". It should show the external drive in the list; from there you just select it, tell it to import everything you want, and wait.

This should recreate your old username with all relevant settings and data already in place. Essentially it should come out as if you were sitting in front of the same computer as before, just with different hardware.