What the seed line actually is
The Mitsubishi NZ2GFS12A2-16DTE sits in the PLC expansion modules class and is described on its listing as a CC-Link IE Field Network module, so it drops onto a CC-Link IE Field segment rather than acting as a CPU or generic I/O block.
Lifecycle and the line-down question
Lifecycle stage is recorded as current, which means the MPN is being specified into new BOM lines rather than pushed through a last-time-buy channel; with no L* successor on the record, there is no official cross-reference to print on the substitution line.
Where the peer sits against it
FX2N-128MR-001 and FX3GA-60MT-CM are FX-series PLC main units, not CC-Link IE Field modules, so all three listed siblings cross a product class boundary against the seed line and none is a same-function alternative.