Hey there,
Just wanted to share my progress since I started the TB series back in Nov 2016. I remember that I didnt have the strength to start the bridge and now I am able to do something more decent :p.
Lack of shoulder flexion was compensated by lumbar spine so after a few months of little progress I started doing the modified TBS with the help of Everett and Jeffrey.
In the modified TBS I ended the series in handstand shoulder flex and repeated some moves again, but I feel that the real progress came from doing cat stretch few times every day. That helped me reducing the bend in the lower back.
Here are some pics in chronological order: