Default [Q] SafeStrap, Rom & Titanium Backup Related Questions

Howdy all - been doing a lot of reading about rooting & custom ROM's and am looking for a little bit of clarification.

My Note 3 had MI9 when I got it and I took the OTA to make it MJ7.

I have root working well & paid version of Titanium Backup installed.

I have Safe Strap 3.65 installed as well.

1. For Titanium Backup - I've done app/system backup. I would use that backup if I froze or uninstalled an app and experienced a problem and needed to unfreeze or reinstall a particular app - correct?

2. For Safe Strap - if I install a custom ROM - I am starting over on my phone from scratch, correct? I would need to setup EVERYTHING - accounts, apps, music, ringtones, calendars, wallpapers, the whole nine yards, right? I can't utilize my Titanium backup to restore any of those settings or apps, can I? I'm just trying to figure out the quickest method to get the phone "re-setup" to my liking after a custom rom or reset.

3. Last question - if I wanted to put my phone back to un-rooted and without Safe Strap - say to turn it back into Verizon at some point - would I just need to use the regular download mode (I believe that's also referred to as Odin - or is Odin something else?) and install a stock MJ7 tar to get it back to that state?

Also, I saw a post that had MJ7 tar & modem - I don't need both, right? The tar would include the modem. The modem is available separate if I wanted to install just that modem, on say, MI9 or something.

I think that's all I need. Just want to make sure I'm prepared for whatever I do in the near future. With Titanium Backup - I've got a pretty nicely running de-bloated phone - so don't know that I "need" a custom ROM - but I like to tinker - so I will probably experiment a little depending on what all the available custom roms have in them.

Thanks for helping me clear these things up!