I have an Indian XT 1550, 6.0.1 Marshmallow, 1 March 2016 Security Patch.
Here's what I did:
Firstly, I downloaded and booted(not permanently installed) the TWRP version 3.1.0-r1.
Then proceeded to take a backup.
After that, I did NOT download the latest version of SuperSU, instead I downloaded the file that OP linked that was verified to work.
Then I installed the SuperSU without putting the SYSTEMLESS flag. (I got a bit too excited and accidentaly forgot about it.

)
I realized the mistake when I saw that it failed to create the ramdisk backup.
I let it reboot and saw that there was no apparent difference when my phone booted up.
I boot up TWRP again. echo'd the systemless to .supersu. Then flashed SuperSU 2.78 (from OP link) again. Ramdisk backup failure again.
I didnt let it reboot, and then proceeded to install the SuperSU 2.62-3 Beta, since this guy is using the same model as my phone.
No errors this time, I thought it was OK. I let it boot up. Bam. com.motorola.ccc has stopped working. also googleplay services. I can't load my homescreen anymore. But thankfully I can use Settings, and connect to my WiFi.
Then, I decided to restore my backup. I booted up TWRP again, and hit Restore. I had ticked all boxes when I backed-up. So it's above 4GB in size. It finished restoring and then I rebooted. Sadly, the problem persists. Still no homescreen and com.motorola.ccc stopped working.. Some apps are updating in the background. I tapped on the notifications and it opened the play store for me through which I can open apps. But that's the only way now.
I tried restoring a couple of times, and installing the latest 2.7.9 version of SuperSU with and without SYSTEMLESS installation.
SuperSU 2.7.9 System Installation went up all the way to "Starting up apps" , but got stuck at that. Rebooting the phone made it stuck at the Motorola stitching animation. Lastly, I did a systemless 2.7.9 which gets me back to the no homescreen problem. I'm not sure where to go from here... :[
Please help.
@acejavelin
EDIT: There's almost no apps installed at this point, not even keyboards. Using the inbuilt speech recognition, I was able to download keyboard, and then downloaded the google now launcher. Strangely.. There's no <u>apparent</u> problem now.. I even downloaded the Root Checker app, which tells me the phone's rooted now.
If you think there's no problem now.. My intention to root was to get LineageOS. Shall I give it a try lol?
EDIT2: There's still some functionality that's not working.. Like the voice recognition thing that was added in Marshmallow.. it says "Google App has stopped working". Is there a way to fix the issue?