From 4.4.4 to patched 5.1.1

The stagefright threat, etc. is forcing me to finally move to 5.1.1. Because one misstep could mess things up, I'm looking for "reassurance" that below is the correct procedure. (I've only upgraded android versions once before and am nervous ....)

Starting point:
- Rooted nexus 5, kitkat 4.4.4,
- Xposed framework installed
- twrp 2.8.6.0 recovery installed
- adb and fastboot on Windows pc

Need to: (please correct if wrong steps)
1. Make nandroid and Titanium backups

2. Download 5.1.1 (LMY48I) from
https://developers.google.com/androi...ges#hammerhead

3. Uninstall xposed framework?

4. Flash downloaded 5.1.1 (LMY48I) from within twrp recovery

Questions:
A. Is 5.1.1 (LMY48I) the correct stagefright patched image for nexus 5?
I'm a T-Mobile subscriber but bought my nexus 5 from Google not T-Mobile. So is this the correct image or the T-Mobile specific 5.1.1 one?
I'm currently KTU84P

B. Will I lose root?

C. Will I lose data?

Please let me know if I have it wrong.

Thank you!