1. PD4ML supports TTF and OTF fonts. OTFs from Win32 distribution are ok, but there are “third-party” OTFs for some reasons not supported by Java (in the case they are skipped in pd4fonts.properties). Usually it helps to open such OTF file in FontForge application and save as TTF. FontForge is an open source tool for UNIX/Linux platform, which is also available for Win32 as “fontforge-mingw”
2. refers to Myriad Pro Light in pd4fonts.properties. refers to Myriad Pro Light Italic, refers to Myriad Pro Light Bold. Also refers to Myriad Pro Light Bold even if there is no tags around. Probably it can explain some oddities with font styles you faced with.