One issue is that there are 2 cracks on the basement floor, running
criss-cross from middle to middle all the way across each way. It
bisects my rectangular basement 2 times and into four equal parts.
Those cracks are straight and have not changed an iota in the six-plus
years of the house's life. Should I seal them with some kind of
concrete repair product or just leave the cracks as they are and build
over them? Should the cracks even be there? The builder said to me
that they were caused by shrinkage/curing and that they are okay. I
wasn't entirely convinced.

I am not an expert in this area. But I guess if the crack doesn't
increase and your doors upstair don't stick. I will not worry about
this.

The house is six years old and I have been running a dehumidifier down
there pretty much nonstop in the summers and autumns these last 2
years. With the Drylok applied, the amount of time it takes for the
dehumidifier's tank to fill has increased dramatically...from twice a
day to twice a week.
The moldy/mildewy smell is gone now - it was pretty bad until I cleaned
the basement, started running the humidifier, threw away or sold a
bunch of the stuff down there, and moved a bunch more to my shed that I
built last year.

This is my experience too with the use of DryLock. But mold and mildew
will still find their way to the bottom of the wall near the floor.
Because you cannot paint over the floor (for various reasons), moisture
will still going up from the floor (such as when rain water is not
being channeled away from the house foundation). Therefore, this is
still very important to channel rain water away from the house
foundation.

The mildew problem in my basement goes away after I have done these:
- Extended the downsprout away from the house foundation.
- Cleaned the mildew from the bottom of the wall really good.
- Run a de-humidifier.

To me it makes the most sense to put in a gap so that, should moisture
seep through the concrete (in the form of vapor), the moisture has
somewhere to go. Then I'd put fiberglass between the studs, paper out,
and find some way to hold it back so that it didn't touch the painted
concrete.

Is there a product out there that will hold the fiber insulation within
the studs so that it does not pop out and touch the concrete?

Put a sheet of plastic between the stud and the basement wall to
separate the fiberglass insulation from the wall. Although you have
DryLock on the wall, moisture will still get through from these
sources:
- There will be a small gap between the wall and the stub because the
wall is not likely to be perfectly straight.
- Moisture from human "may" find its way through the drop ceiling to
the back of the stud wall and reach the fiberglass insulation.

I am not sure how bad these sources of moisture can be. But I would
much rather to use plastic sheet cover both sides of the stub wall to
avoid any moisture from reaching the insulation material.

A lot here I know, but I've pretty much decided how I'm going to do
this...I just hope that someone can chime in here and let me know if I
have my head up my butt. Everything I've read indicates that there is
no "right" way to finish a basement...once you decide to finish it,
there's nothing to stop water from coming in if it wants to. What I'm
trying to do is make reduce the risk of water vapor seapage condensing
onto any surfaces.

You may want to make sure the finished basement will have enough
verical height after you have added drop ceiling and raised the floor.
A low ceiling finished basement is not very appealing for the amount of
work that you need to invest into finishing it -- you may get used to
the low ceiling though.

Leveling the floor with leveling compound is the most difficult part of
finishing a basement -- ignoring the issues of heating and cooling and
electrical works. If you get enough vertical height in the basement,
you may be better off using a raised floor as a way to level the floor
instead of using leveling compound.

Good luck.

Jay Chan