Cool, I’m glad you got it working!.. 
I’m fairly certain they must have done something to fix it unless you can confirm your method works in 4.7 or 4.8 because I’ve tried this among other things. I mean to add a body for the root… etc. and I haven’t been able to get good results. But, again, I haven’t tried this since 4.7 or 4.8.
If I remember correctly the problem I always had was with the root not staying… at the root, so when I tried to basically lock it down using this method you describe, that was ok, the root stayed there, but it still didn’t work out properly. I think it was with aligning the capsule, there was a reaction on the ragdoll. If I remember correctly what it did was pull the ragdoll around, even though it was technically “disconnected”, not constraints, or anything. So I couldn’t align the capsule, no matter what I tried. I actually could get good blending, if I left the capsule alone. There were some definite problems with it. I think, that was it.
If you got it working, I can try mine as well and see what’s the result, if I get something different from before. I’m sure once I start looking at it again, it’ll jog my memory on things. But from the sounds of it, and from what I can remember about my earlier attempts, it sounds like, they may have changed things to make that function correctly.
But anyway, that’s good news, it gives me a reason to check it out again…