A lot of questions there, but I’ll try to address a few:
All three choices work with motion blur, but I would build it by animating the camera–stay away from scaling it.
To make it really easy on yourself, you can just build 1 comp with the camera animating all the way through the move with one piece of text. Then render the whole thing with another piece of text.
Create the text first, then make it 3D. Then create a new camera. Leave the text at the default position–in fact, lock it so it doesn’t move. Go to the end of your comp and set a position keyframe. Go the beginning of your comp and adjust the z-position of the camera until it’s as far back as you want to go. Duplicate the comp and change the text (or option drag your new text to the selected old text). Repeat. Render all 9 comps after your done.
Then in your video editor you can choose which parts you want to use to make it look like the text is getting closer to camera–which will inevitably change as you see it in sequence.
As long as you build your text (in Photoshop or something) as big as it will ever appear in camera (ie if your comp is 1920×1080 and you happen to want your text to fill the screen completely then build your text at 1920×1080.) Making the titles in AE and Illustrator will allow you to use the “continuously rasterize” checkbox and you’ll never have to worry about size and pixellation.
There’s no easy way to fix title safe in a bunch of comps, but if you do it my way with the camera, you can just fix the camera in one comp and paste the same camera into the other comps.
I would put your background in a pre-comp and then copy that single pre-comp into your 9 main comps–that way you can just change one to ripple through all of them.
Maybe start here:
AE Basics
https://blogs.adobe.com/toddkopriva/2010/01/getting-started-with-after-eff.html
3D basics (Animating a camera):
https://www.videocopilot.net/basic/#07
Dan Fredley