Yes, a PASC/MP1 file compressed with any encoder, using any psycho-acoustic model, would play on any MP1 decoder. The PASC/MP1 data stream is basically a list of instructions to the decoder to tell it how loud to play each frequency. The data reduction is completely a matter of reducing the accuracy at encoding time.
The psycho-acoustic model is used during encoding to decide which frequencies need to be encoded at which accuracy. At decoding time, the psycho-acoustic model is completely irrelevant.
The psychoacoustic model used in all DCC recorders is the same, because the DCC system specification mandates that all DCC recorders use the algorithm that it describes. However after DCC came out, there were some smart people who came up with newer psycho-acoustic models (I think there were 3 in total but I could be wrong). The nice thing is that it’s perfectly okay to use those during encoding; every decoder will be able to handle the data stream.
Yes, that is possible (assuming Steinberg Wavelab has a working MP1 encoder). If you want to release a DCC tape, you can do your own encoding like that. The only problem is then that you have to somehow get your PASC/MP1 files recorded on tape. Currently the only way to do that is by using the DCC-175 and a PC-cable, connected to a Windows 95/98 computer. I’m working on a way to make it possible with other DCC recorders and modern hardware.
VLC uses LAME to decode MP1 if I recall correctly. Unfortunately LAME is only a decoder, not an encoder. It was actually pretty difficult to find an MP1 encoder that worked under Windows 10. I used MP2ENC after I made some improvements(*). It works very well as far as I know, and I hope to integrate it into a bigger program one day.
(*) MP2ENC didn’t support 24 bit WAV files originally, and used 16 bit floating point operations. Also it had bugs that made it choke upon certain characters in the input, and it had a bug where it would process the ID3 label as audio.