Others can probably answer using SEQ better than I can, I have used it some to develop sequences.
First the easy part, which version of firmware to use with the SSC-32. To use sequences you must have a version whose name ends with the letters GP (General Purpose), not the ones that end with XE. I use the versions that end with the 3 letters EGP (Extended...). The EGP versions support communicating in binary mode as well as ASCII command set... I have mine programmed with 2.07EGP...
Next: Usually when I hear about issues like you are having, the first three things I think about are:
That is if it worked yesterday, but not today, the first thing I would do (assuming you changed over to using battery instead of 2amp wall wart) would be to charge my battery. The next thing I would do, would be to make sure that I am not having VS=VL. If I did, I would undo this and try connecting a 9v battery to VL. Why? Often what happens is all of the servos try to move at once which causes a surge to the main battery, where the voltage drops and for a moment gets too low, which causes the processor on the SSC-32 or likewise processor board connected to SSC-32 to reset...
As for what software to use on a humanoid robot. In the end you will probably need some main processor doing stuff. How you do it, well, there are lots of options:
a) Use SEQ to generate a set of sequences and have your main program decide which of these sequences to run... The closest I have come to this is to run some canned sequences on the hexapods...
b) Similar but on the Brat, we developed a set of canned sequences, where we had a function that said move the leg servos to this angle, and then when you told it to do something, it would run through a sequence. Most of the brat code version were real simple, they would get input from the PS2, decide on which command they wanted to run and then do the command, some of that code looked like:
if(command = 1) then ; Walk Forward
gosub movement [ 7.0,-20.0,-20.0, -7.0, 20.0, 20.0, 500.0]
gosub movement [ -7.0,-20.0,-20.0, 7.0, 20.0, 20.0, 500.0]
gosub movement [ -7.0, 20.0, 20.0, 7.0,-20.0,-20.0, 500.0]
gosub movement [ 7.0, 20.0, 20.0, -7.0,-20.0,-20.0, 500.0]
elseif(command = 2) ; Walk Backwards
The function movment was defined:
I have a slightly more complicated version that I ported to arduino, that was table driven instead and that could detect stuff while running a sequence, but the idea was same.
c) You can drive the whole thing using IK code, like we do with the Hexapods. For this I suggest you take a look at Zenta's (Kåre) Archer project. viewtopic.php?f=7&t=6342
But: The math makes my head hurt