I wouldn't call them defects. It was more a case of that custom sound effects created for MT-32 (Old) wouldn't sound the same on MT-32 (New) and CM / LAPC-I units.

And yes, as long as you give Munt ROMs from a MT-32 (Old), it will play these sound effects. Sierra and Dynamix are good games to test this 😀

The correct answer would be "yes and no". The defects thecrankyhermit means are software bugs in reality. As we know, no functional change related to the core synth chip LA32. Those bugs allowed composers to go out the bounds specified by Roland for various patch properties and create sounding impossible to achieve otherwise. So, newer units rather "functionally limited" in this respect 😀

Besides that, there are changes in both digital and analog audio circuits targeted to improve overall sound quality, notably the reverb. Munt is aimed to accurately emulate all these stuff but we're currently paused on some of the Control ROM bugs still not emulated (mostly due to lack of time to perform accurate analysis of Control ROM code).