I am here to confirm that it does work.
I was already on stock rooted lollipop before flashing. Here is what I did from there.
1. Downloaded the tmobile alliance ROM from this website to micro sd card
2. Reboot to SS. If you are already on lollipop then you will need the NC2 flasher from here.
4. Install ROM
5. Reboot to download mode
6. Odin the N900A_OC1_ALL_Other_Stock_Partitions.tar.md5 using Odin's PDA slot.
Phone will take a while to boot. Just be patient.
After the phone came up, I went to settings..general..applications...running .... and found every Tmobile app and cleared cache and disabled them. The real important one here is the Visual Voicemail. Otherwise it will keep on trying to contact Tmobile and then you will get text messages saying there is an error.
Wifi Calling is throwing a sim card error (as you would expect). Only problem is it is shown in status bar and lockscreen. I'm sure there is a way to hide it or disable it. I just haven't had a chance to figure it out.
Hope this helps.