I guess there could be a debate about the pros/cons of Titanium vs. MyBackupPro forever. I personally use MBP, though I do have TiBu but have been using it less and less, since I've paid for MBP. I'll use MBP to backup apps (.apk's with data), then I'll use it to backup data; call logs, bookmarks, sms, and mms.
However, I did find what looks to be the end-all method of using TiBu:
http://androidforums.com/droid-all-things-root/241380-ti-backup-question.html#post2038550
just to show I'm not closed minded.
Anyways, I'm pretty much like androidlover14, but here's my own twist:
1. To a certain extent, yes, but that's why you can 'mount usb storage' to your pc, right? Copy/paste, then delete from sdcard; unmount usb storage.
2. Every time you feel comfortable that you don't need an immediate restore from you last change.
Before I answer your #3 I would like to make a clarification. Your list included ClockworkMod, Lookout, and Nandroid. I am not familiar with Lookout, but any custom recovery image will include a Nandroid option. It is actually Nandroid that makes the backup, but which ever custom recovery that you use will determine the actuall location of your nandroid backups. In your case you're using CWRecovery:
3. [/sdcard]/clockwork/backup
4. Yes. But in some very different ways. The nandroid backup is akin to a setting a system restore point on your Windows computer. The TiBu and/or MBP is akin to a backup/restore settings and apps on a Windows computer.
5. Here, again the debate could continue. For this read up.
good luck