The NYCTA is building out a TETRA pilot system on 700 MHz. It is expected that if the pilot system is successful, the entire buildout will be TETRA incorporating both 700 and 800 MHz frequencies.
The reference to "Phase 1" and "Phase 2" are simply the design and rollout phases of the system itself; not a reference to P25.
The proximity of the NYCTA and NJT has no bearing on interference issues simply because they are both TETRA systems. Any interference issues would be on co-channels or adjacent channels, not the proximity of two separate systems.
Also, when looking at their licenses, remember to pay attention to conventional SG vs trunking SY, as they have both.
Oh and by the way, the "point of using TETRA" is that the subscriber equipment is much cheaper than P25.