On the parameter spliting etc. Take a look at module based runtime proposal in F0 and see if it meet most of the need. The ideal is that the factory module will create separate runtimes for each of the model. Rather than a single executor for all models (so you don’t have to differentiate between output of each model).
It is harder to name the output, as while input are parameters of the function(thus can be named), the output is not and from the functional module it is a tuple(and not named by default), in the same order of the original function.
The names in F1 is related to the codegen phase(symbol name in the libs), so it might be possible to rename and remap them by adding an additional renaming pass. However, that might need some additional works, as it can affect both the relay phase and lowering.