Rooting - I'm on the right track?

Just want to be sure before I continue.

Right now I'm on MIUI STABLE 7.3(7.3.7.0(LHOMIDD), I still want to stay on stock ROM but have root access via SuperSU, in order to have this I will unlock my phone OFFICIALLY(will i need to flash China Developer Version?).
- then Flash Cofface TWRP
- then Flash SuperSU

Finished?

My concerns - I will not be able to run MIUI Stable?

Samsung S6 Edge lost track of media / pictures / directory structure changed

Just a quick one folks, a couple of weeks ago I was alarmed to see my pictures had suddenly dissapeared from the gallery, and no amount of messing seemed to get them back. I downloaded a file explorer and found them once again in >root>sdcard>DCIM>camera. New pictures seem to be stored in >root>sdcard>Pictures.
Anyway so at least they are not lost.

However this change has also affected music. I can only navigate to music files with VLC, all other media players I have tried do not show anything at all. When I select a track as usual VLC will play that track then stop playing! I have tried moving the directory without luck.

I would rather not reset the phone, so if anyone has any ideas as to what can be the matter let me know.

Phone is standard EE