[AT&T HTC One (M7)] wedel219:
Soft-bricked HTC One M7, restored with stock rooted ROM, still having problems

[tl;dr]: Please skip to the bottom for a list of my questions. Specs follow that. Otherwise, please read the long version. :)

I tried flashing Android Revolution HD 6.1 Google Edition (that's the download link to the zip) and it soft-bricked my phone, sending me into a boot loop into recovery.

I wiped my phone and flashed the ROM found at [ROM][4.4.2] - AT&T 4.18.502.7 Stock Rooted, which brought my phone back to working order, though with changes from the ROM I'd had originally, from before unlocking my bootloader and rooting my phone.

Before unlocking the bootloader, I made a number of adb backups. After initially rooting my phone, before flashing any ROMS, I restored my backup with adb then made a backup of that in TWRP. Downloaded Titanium Backup and made a backup with that, too. I copied both TWRP and Titanium backups to my PC.

After the Android Revolution flash went bad, I had to use the AT&T 4.18.502.7 Stock Rooted ROM. I was able to again restore most of my data and settings with adb, but with the failed flash and soft-bricking, I lost the local backups on my phone. Since restoring the OS and being able to see my phone with my computer, I cannot copy my TWRP backup to my phone's /sdcard/TWRP/BACKUPS directory.

I was able to move my TitaniumBackup folder to /sdcard but, when I tried restoring the system data and apps + data, I wound up losing my IMEI, my Phone Number ... presumably because the radio firmware for my original OS and the ROM I used to recover were not the same.

I wiped again, flashed the stock ROM for my firmware again and restored my adb backup again. Adb backup did not save my contacts nor my texts but I made an HTC Sync backup, which restored them.

Perhaps none of this would seem like a crisis to a seasoned developer, but I am a total neophyte. I wasn't expecting this all to be easy, but I wasn't expecting it to be as difficult (or as roundabout, more accurately) as it has been. So, I've got some questions:

I thought making a TWRP backup = NANDroid backup, but output is not a zip file (it contains four files: boot.emmc.win, boot.emmc.win.md5, data.ext4.win, data.ext4.win.md5) and I cannot copy it to my phone: How, then, do I restore my own stock ROM?

Is there a way to save OS, apps, Contacts and texts (and anything else someone might reasonably want to preserve) in one place, easily restorable?

I cannot restore system data from Titanium because the stock ROM I used for recovery has differences that cause conflicts, particularly with the radio firmware: Do I have to just let my system settings go, and recustomize the phone manually?

Why did trying to flash a ROM that is for Android 4.4.2 -- which is the version I have -- brick my phone?

I'd love for this to turn into a conversation from which I can learn. I have more questions, but this post is plenty long enough, I think.

Specs:
Model: HTC One
Android Version: 4.4.2
Sense Version: 5.5
Software Number: 4.18.502.7
HTC SDK API level: 5.68
Kernel: 3.4.10-ge12f77e (root@amb012 #1, SMP Preemp (NO IDEA WHAT THIS MEANS))

Bootloader:
*** TAMPERED ***
*** UNLOCKED ***
M7_UL PVT SHIP S-ON RH
HBOOT-1.56.0000
RADIO-4T.24.3218.09
OpenDESP-v32.120.274.0909
OS-4.18.502.7
eMMC-boot 2048MB
Jan 28 2014,09:32:41.0

Would love to know how each of those properties affect what ROMs I can use. I'd love to know how not to brick myself again. Thanks in advance.