Well the project is over, I poured the concrete in last night.

I wish I knew about there being a diamond tipped blade and the water
before I did the cutting, I am still cleaning up the dust (it got
everywhere).

The inspector did not like the idea of using an island vent, but
accepted it after seeing the complications that would be encountered
by trying to go up the wall for a more traditional vent.

However, the plumber that put in the island vent did not have the vent
pipe low enough, at the end it was sticking above the concrete. The
plumber said that it could not be avoided because of where the drain
was, the connectors and the pitch that the connectors must be. The
inspector failed it though, because it stuck out of the concrete, and
that could cause the pipe to crack. The inspector told the plumber to
lay the connector, from the drain to the vent, down horizontally. The
plumber told me that doing that is not right and is not up to code,
but if that is what the inspector wants then that is what he will do.

The U-shaped part of the island vent, the part that goes up and then
down inside the wall, needed to be at least six inches above the
counter top height.

The water pipes to the bar sink needed air chambers on them, the
inspector said that even the pipe to the refrigerator, for the ice
maker, should have one, but would be ok once the air chamber was put
on for the sink.

Anyway the plumber came back out quickly and fixed everything, and was
very pleasant. So I am really glad that I had them do it. It cost me
$450 to have them lay the drain and vent pipes. I have no idea if
that is a good price. The inspector said it seemed high to him, but
the other quotes I got just for laying the pipes were over $1,000.

I put rock back into the hole, just enough to cover the pipes, and
then put plastic over the rock, when I dug the hole there was plastic
between the rock and the concrete, so I just mimicked that. I had
about 27 square feet, to fill in and must not have had a full 4 inches
some where, because it only took 12 bags of 80 lbs. concrete mix (the
kind you just add water to). The bag said it should take 14 bags for
24 square feet for a 4 inch pour. Other than being a little
interesting to get smooth and level, this was very easy and took less
than three hours to pour. I re-smoothed it out about once every hour,
a little obsessive, but hey its boring watching concrete dry.

I would like to thank James from AAA AceCo for laying the drain and
vent pipes.

I would also like to say thanks to all who posted.