Geez man your getting way to complicated, although it sounds about right, although the upper limit on the 400 and 777 is V2 + 15 for eng out and V2+25 all engines. It's a rather complicated section in the FCOM 1, and rather dry reading!!
In CX we use the standard Boeing way, the FD's do not give correct pitch info with TOGA after liftoff until VNAV engages at 400'. This is the way on the 777 anyway. I think the 400 was the same. (Anyway it's only a 5 to 6 second wait)
So, on a normal T/O nail 15 deg on a 772 and 12.5 deg on a 773. Eng out nail about 10 deg on both. After a nice slow rotation it will give you the right speed.