Re: EBI and Ethernet on 100-pins chips PIC32MZ.
AEREFCLK, AERXDV are alternate pins for Ethernet signals, selected by configuration bit FETHIO,
but on 100 pin device, EREFCLK and AEREFCLK seem to be the same pin.
May also depend upon what use you want of EBI.
Not all uses of EBI, will need to use all Address pins of EBI.
E.g graphics interface may use EBI without address pins, but if you want EBI to address external memory you may need a different package.