Formerly the Park Jersey Diner, 1135 E. Jersey St., Elizabeth, NJ. Currently operating as Martin’s Sandwich Shop.
This is a large ’50s diner, sited perpendicular to the road. While it has received the mansard treatment, and a faux-tudor half timbered front, the stainless steel along the windows is still visible, as is the curve of the foundation and corner stainless at the bottom, despite the upper part of the diner having had the corner squared off. I like how the original sign post cuts a hole through the faux mansard. A picture with significantly more detail can be found here.

This next one is also fairly clear cut. Formerly Scot’s Diner, 1551 Main Ave, Clifton, NJ
Now operating as the Baranda Restaurant. Exterior still recognizable, interior looks gutted from what I’ve been able to find.

The next one is a bit more shaky as to what’s left, as the renovation is more complete. This is the site of the former Queens Diner, 531 Van Houten Ave, Clifton, NJ. The size and the proportions match for a diner, as dies the height of the foundation. While the best known Dunkin Donuts diner conversion is probably the former Short Stop Diner in Bloomfield, I have found several other specific references to Dunkin remodeling former diners as opposed to tearing them down, so it wouldn’t surprise me to find that this was the case here. The design of the building, incongruous with what Dunkin purpose builds supports that. But as to what the place is or was, at this juncture is anyone’s guess.