First you have to decide creatively what you want the restaurant to look like.
The drop ceiling makes things easier, for small units like Peppers and Dedos, and single bare Kino tubes, a scissor clamp is probably enough to mount the light, and for anything heavier, you can pop open a panel and see if there is some stronger architectural elements to c-clamp onto (as long as that part of the ceiling will be off-camera.)
Speaking in vague generalities, I would tend to break this down into three areas / issues: the bar area, the tables, and the general ambience. I'd probably start with the bar -- you need to motivate some light on the faces of the patrons at the bar. In close-ups, you can soft-light them as if they were lit by the glow of the neons and bar lights, but in the wide shots, you need a little something to augment or key the people sitting there. One option that I often use is to put a couple of Peppers or Dedos in a row in the ceiling above the bottles along the back wall, pointed down and out towards the bar. In a wide shot, that can look like track lighting up there. I often also would put a strip of lights behind the bottles to backlight them -- either Kino tubes, Linestra tubes, or a row of LED's on a strip of wood. You can gel or dim them for color, just depends on the look you want.
You could also try a strip of lights along the bar top itself -- I've used bare Kino tubes in the past but it sometimes looks too high-tech and "Blade Runner"-ish. Maybe a rope light or string of LED's would work better these days. Then people could be uplit rather than lit with a row of Peppers in the ceiling.
Now throughout the restaurant, you can also add some Peppers or Dedos for small color spots that can serve as backlights in the close-ups.
For the tables themselves, very small table lamps are a nice idea but you'd need to run zip cords to all the tables and tape down the cords so that no one would trip on them. if your camera is sensitive enough, some battery-powered LED practicals may be enough, like a cluster of these flameless LED candles.
Otherwise, you'd have to light the tables from the ceiling and then you get into more rigging to hide, put you could have a few tables with a small hot top light spotted on the center of the table that bounced back up on people's faces. And you could put some color-gelled Kino tubes in parts of the ceiling for the colored fill on the room.
Another option is floor mounted Source-4 Lekos pointed straight-up into the white ceiling, and dimmed way down. You can even hide the fixture in a tube or box of some sort created by the art department, something that "Argo" did for a scene.
Again, all power has to be taped down and heavier cables need slip-proof rubber mats over them.
Also, you need to figure out your power restrictions, this is where low-wattage LED's and other small units would be an advantage if you are forced to use house power. A lot of bars and restaurants are already pretty maxed out on power due to refrigerators and whatnot running off of the wall circuits.