As you discover, simply none of the srfs tool works.
The problem is in the curve layout. This layout is, simply, impossible.
I can understand you took long time fixing all the curves, but, sorry, it’s just the starting point, not the end.
A surface MUST have a rectangular layout (topology) so you have to subdivide your curve structure to get as much 4 sides you can.
Specially in the right part, were the horizontal intersect the vertical the layout it’s particularly bad.
You can’t get any perfect solution, you must accept a certain tolerances between the created and the srf,not because Rhino3D is not precise, but because your construction isn’t perfect.
Hope this can help you.
Take a read of this post Modeling a mixer
It has a very similar question.
Bye.I